onNewSyncSource without DataPortNo

Hi,
to manage connected clients in a server i like to register them with
networkAddress, DataPortNo, ControlPortNo
Normally this info should be available in the SyncSource object. Now i run
into problems, cause the DataPortNo 
is not set (0)if OnNewSyncSource is called. Is there a trigger or callback
when the info is complete, or is there
a way to force that the OnNewSysncSource is called only from incoming Data?

already now have many thanks for your answers

Martin Mainka