--- a/qtms/src/qtmsgaineffectimpl.cpp	Wed Jun 16 16:05:08 2010 +0100
+++ b/qtms/src/qtmsgaineffectimpl.cpp	Thu Jul 22 16:38:21 2010 +0100
@@ -57,13 +57,14 @@
     }
 
 gint QTMSGainEffectImpl::AddObserver(TMS::TMSEffectObserver& obsrvr,
-        gpointer /*user_data*/)
+        gpointer user_data)
     {
     gint ret(QTMS_RESULT_SUCCESS);
 
     if (iEffect)
         {
-        ret = static_cast<TMSGainEffect*> (iEffect)->AddObserver(obsrvr, NULL);
+        ret = static_cast<TMSGainEffect*> (iEffect)->AddObserver(obsrvr,
+                user_data);
         }
     return ret;
     }