diff --git a/src/exchange/taler-exchange-httpd.c b/src/exchange/taler-exchange-httpd.c
index d9d372809..59398c6fc 100644
--- a/src/exchange/taler-exchange-httpd.c
+++ b/src/exchange/taler-exchange-httpd.c
@@ -150,7 +150,7 @@ bool TEH_suicide;
 /**
  * Global register of extensions
  */
-struct TALER_Extension *TEH_extensions;
+struct TALER_Extension **TEH_extensions;
 
 /**
  * Value to return from main()
diff --git a/src/exchange/taler-exchange-httpd.h b/src/exchange/taler-exchange-httpd.h
index 543d1b90f..dec62c3bb 100644
--- a/src/exchange/taler-exchange-httpd.h
+++ b/src/exchange/taler-exchange-httpd.h
@@ -204,7 +204,7 @@ extern struct GNUNET_CURL_Context *TEH_curl_ctx;
 /**
  * The manifest of the available extensions, NULL terminated
  */
-extern struct TALER_Extension *TEH_extensions;
+extern struct TALER_Extension **TEH_extensions;
 
 /**
  * @brief Struct describing an URL and the handler for it.
diff --git a/src/exchange/taler-exchange-httpd_extensions.c b/src/exchange/taler-exchange-httpd_extensions.c
index 24d4dc469..938470811 100644
--- a/src/exchange/taler-exchange-httpd_extensions.c
+++ b/src/exchange/taler-exchange-httpd_extensions.c
@@ -24,47 +24,94 @@
 #include "taler-exchange-httpd_extensions.h"
 #include "taler_json_lib.h"
 #include "taler_mhd_lib.h"
+#include "taler_extensions.h"
 #include <jansson.h>
 
 /**
- * Create a list with the extensions for Age Restriction and Peer2Peer
- *
- * TODO oec
+ * @brief implements the TALER_Extension.parse_config interface.
  */
-static struct TALER_Extension *
-register_known_extensions ()
+enum GNUNET_GenericReturnValue
+TALER_Extension_AgeRestriction_parse_config (struct TALER_Extension *this, const
+                                             json_t *config)
 {
-  /* TODO oec
-   * - create list of correct size, or linked list?
-   * - fill data for age restriction and peer2peer
-   * - set function pointers for parser and json-converter
-   * - set function pointers for notimplemented?
-   */
-/**
- * The global manifest with the list supported extensions, sorted by
- * TALER_Extension_Type.
- *
- * TODO: This needs to become a dynamic list, once we have a model for
- * extensions as plugins.
-struct TALER_Extension *TEH_extensions[] = {
-  [TALER_Extension_AgeRestriction] = {
-    .type = TALER_Extension_AgeRestriction,
-    .name = "age_restriction",
-    .critical = false,
-    .config = NULL, // disabled per default
-    // .parse_config = &TALER_Extension_AgeRestriction_parse_config,
-    // .config_to_json = &TALER_Extension_AgeRestriction_config_to_json,
-  },
-  [TALER_Extension_Peer2Peer] = {
-    .type = TALER_Extension_Peer2Peer,
-    .name = "peer2peer",
-    .critical = false,
-    .config = NULL, // disabled per default
-  },
-};
- **/
+  enum GNUNET_GenericReturnValue ret;
+  struct TALER_AgeMask mask = {0};
 
-  return NULL;
+  ret = TALER_agemask_parse_json (config, &mask);
+  if (GNUNET_OK != ret)
+    return ret;
+
+  if (this != NULL && TALER_Extension_AgeRestriction == this->type)
+  {
+    if (NULL != this->config)
+    {
+      GNUNET_free (this->config);
+    }
+    this->config = GNUNET_malloc (sizeof(struct TALER_AgeMask));
+    GNUNET_memcpy (this->config, &mask, sizeof(struct TALER_AgeMask));
+  }
+
+  return GNUNET_OK;
+}
+
+
+/**
+ * @brief implements the TALER_Extension.config_to_json interface.
+ */
+json_t *
+TALER_Extension_AgeRestriction_config_to_json (const struct
+                                               TALER_Extension *this)
+{
+  const struct TALER_AgeMask *mask;
+  if (NULL == this || TALER_Extension_AgeRestriction != this->type)
+    return NULL;
+
+  mask = (struct TALER_AgeMask *) this->config;
+  json_t *config =  GNUNET_JSON_PACK (
+    GNUNET_JSON_pack_string ("extension", this->name),
+    GNUNET_JSON_pack_string ("mask",
+                             TALER_age_mask_to_string (mask))
+    );
+
+  return config;
+}
+
+
+/* The extension for age restriction */
+static struct TALER_Extension extension_ageRestriction = {
+  .type = TALER_Extension_AgeRestriction,
+  .name = "age_restriction",
+  .critical = false,
+  .config = NULL,   // disabled per default
+  .parse_config = &TALER_Extension_AgeRestriction_parse_config,
+  .config_to_json = &TALER_Extension_AgeRestriction_config_to_json,
+};
+
+/* TODO: The extension for peer2peer */
+static struct TALER_Extension extension_peer2peer = {
+  .type = TALER_Extension_Peer2Peer,
+  .name = "peer2peer",
+  .critical = false,
+  .config = NULL,   // disabled per default
+  .parse_config = NULL, // TODO oec
+  .config_to_json = NULL, // TODO oec
+};
+
+
+/**
+ * Create a list with the extensions for Age Restriction and Peer2Peer
+ */
+static struct TALER_Extension **
+get_known_extensions ()
+{
+
+  struct TALER_Extension **list = GNUNET_new_array (TALER_Extension_Max + 1,
+                                                    struct TALER_Extension *);
+  list[TALER_Extension_AgeRestriction] = &extension_ageRestriction;
+  list[TALER_Extension_Peer2Peer] = &extension_peer2peer;
+  list[TALER_Extension_Max] = NULL;
+
+  return list;
 }
 
 
@@ -115,7 +162,7 @@ extension_update_event_cb (void *cls,
     enum GNUNET_DB_QueryStatus qs;
 
     qs = TEH_plugin->get_extension_config (TEH_plugin->cls,
-                                           TEH_extensions[type].name,
+                                           TEH_extensions[type]->name, // FIXME oec
                                            &config);
 
     if (qs < 0)
@@ -139,22 +186,24 @@ extension_update_event_cb (void *cls,
 enum GNUNET_GenericReturnValue
 TEH_extensions_init ()
 {
-  // TEH_extensions = register_known_extensions();
+  TEH_extensions = get_known_extensions ();
 
-  struct GNUNET_DB_EventHeaderP ev = {
-    .size = htons (sizeof (ev)),
-    .type = htons (TALER_DBEVENT_EXCHANGE_EXTENSIONS_UPDATED),
-  };
-
-  extensions_eh = TEH_plugin->event_listen (TEH_plugin->cls,
-                                            GNUNET_TIME_UNIT_FOREVER_REL,
-                                            &ev,
-                                            &extension_update_event_cb,
-                                            NULL);
-  if (NULL == extensions_eh)
   {
-    GNUNET_break (0);
-    return GNUNET_SYSERR;
+    struct GNUNET_DB_EventHeaderP ev = {
+      .size = htons (sizeof (ev)),
+      .type = htons (TALER_DBEVENT_EXCHANGE_EXTENSIONS_UPDATED),
+    };
+
+    extensions_eh = TEH_plugin->event_listen (TEH_plugin->cls,
+                                              GNUNET_TIME_UNIT_FOREVER_REL,
+                                              &ev,
+                                              &extension_update_event_cb,
+                                              NULL);
+    if (NULL == extensions_eh)
+    {
+      GNUNET_break (0);
+      return GNUNET_SYSERR;
+    }
   }
   return GNUNET_OK;
 }
diff --git a/src/exchange/taler-exchange-httpd_management_extensions.c b/src/exchange/taler-exchange-httpd_management_extensions.c
index 4902677ae..61ba771ce 100644
--- a/src/exchange/taler-exchange-httpd_management_extensions.c
+++ b/src/exchange/taler-exchange-httpd_management_extensions.c
@@ -128,7 +128,7 @@ set_extensions (void *cls,
 
     qs = TEH_plugin->set_extension_config (
       TEH_plugin->cls,
-      TEH_extensions[ext->type].name,
+      TEH_extensions[ext->type]->name, // FIXME oec
       config,
       sig);
 
@@ -258,6 +258,8 @@ TEH_handler_management_post_extensions (
 
     /* 2. Make sure name refers to a supported extension */
     if (GNUNET_OK != TALER_get_extension_by_name (name,
+                                                  (const struct
+                                                   TALER_Extension **)
                                                   TEH_extensions,
                                                   &extension))
     {
diff --git a/src/include/taler_extensions.h b/src/include/taler_extensions.h
index 62e371312..a7cda9fbf 100644
--- a/src/include/taler_extensions.h
+++ b/src/include/taler_extensions.h
@@ -72,7 +72,7 @@ struct TALER_Extension
  */
 enum GNUNET_GenericReturnValue
 TALER_get_extension_by_name (const char *name,
-                             const struct TALER_Extension *extensions,
+                             const struct TALER_Extension **extensions,
                              const struct TALER_Extension **ext);
 
 /*
@@ -112,6 +112,19 @@ TALER_parse_age_group_string (char *groups,
                               struct TALER_AgeMask *mask);
 
 /**
+ * Encodes the age mask into a string, like "8:10:12:14:16:18:21"
+ *
+ * @param mask Age mask
+ * @return String representation of the age mask, allocated by GNUNET_malloc.
+ *         Can be used as value in the TALER config.
+ */
+char *
+TALER_age_mask_to_string (const struct TALER_AgeMask *mask);
+
+
+/**
+ * @brief Reads the age groups from the configuration and sets the
+ * corresponding age mask.
  *
  * @param cfg
  * @param[out] mask for age restriction, will be set to 0 if age restriction is disabled.
diff --git a/src/util/extension_age_restriction.c b/src/util/extension_age_restriction.c
index c0efd7cd1..42a58b2e9 100644
--- a/src/util/extension_age_restriction.c
+++ b/src/util/extension_age_restriction.c
@@ -23,7 +23,6 @@
 #include "taler_extensions.h"
 #include "stdint.h"
 
-
 /**
  *
  * @param cfg Handle to the GNUNET configuration
@@ -137,12 +136,14 @@ TALER_parse_age_group_string (char *groups,
 
 
 /**
+ * Encodes the age mask into a string, like "8:10:12:14:16:18:21"
+ *
  * @param mask Age mask
  * @return String representation of the age mask, allocated by GNUNET_malloc.
  *         Can be used as value in the TALER config.
  */
 char *
-TALER_age_mask_to_string (struct TALER_AgeMask *m)
+TALER_age_mask_to_string (const struct TALER_AgeMask *m)
 {
   uint32_t mask = m->mask;
   unsigned int n = 0;
diff --git a/src/util/extensions.c b/src/util/extensions.c
index 33f76d466..32de94d64 100644
--- a/src/util/extensions.c
+++ b/src/util/extensions.c
@@ -25,13 +25,13 @@
 
 enum GNUNET_GenericReturnValue
 TALER_get_extension_by_name (const char *name,
-                             const struct TALER_Extension *extensions,
+                             const struct TALER_Extension **extensions,
                              const struct TALER_Extension **ext)
 {
 
-  const struct TALER_Extension *it = extensions;
+  const struct TALER_Extension *it = *extensions;
 
-  for (; it->type != TALER_Extension_Max; it++)
+  for (; NULL != it; it++)
   {
     if (0 == strncmp (name,
                       it->name,