Index: src/dbus/dbus-message.c
===================================================================
--- src/dbus/dbus-message.c	(revision 21386)
+++ src/dbus/dbus-message.c	(working copy)
@@ -1227,6 +1227,13 @@
       return NULL;
     }
 
+  if(message_type == DBUS_MESSAGE_TYPE_SIGNAL ||
+     message_type == DBUS_MESSAGE_TYPE_ERROR ||
+     message_type == DBUS_MESSAGE_TYPE_METHOD_RETURN)
+    {
+      dbus_message_set_no_reply (message, TRUE);
+    }
+
   return message;
 }