diff --git a/src/core/sat_main.py b/src/core/sat_main.py
index cc896e08..2d8e1a73 100644
--- a/src/core/sat_main.py
+++ b/src/core/sat_main.py
@@ -55,8 +55,8 @@ class SAT(service.Service):
         self.initialised = defer.Deferred()
         self.profiles = {}
         self.plugins = {}
-        self._ns_map = {}  # map for short name to whole namespace
-
+        self._ns_map = {u'x-data': u'jabber:x:data'}  # map for short name to whole namespace,
+                                                      # extended by plugins with registerNamespace
         self.memory = Memory(self)
         self.trigger = trigger.TriggerManager()  # trigger are used to change SàT behaviour