c# RTD Server, IRTDUpdate Object

[heribert]

I'm trying to implement a RTDServer for Excel in C#. How can I cause
Excel to update my data?
I tried to call the UpdateNotify function on the IRTDUpdateEvent
Object, but nothing happened.The reference to the IRTDUpdateEvent does
not work. I can't even change the HeartbeatInterval. The
Microsoft.Office.Interop.Excel.IRtdServer.RefreshData function is never
called. ServerStart, ConnectData, DisconnectData, ServerTerminate are
properly called by Excel.
Is there something wrong with the reference to the IRTDUpdateEvent
object?

int
Microsoft.Office.Interop.Excel.IRtdServer.ServerStart(Microsoft.Office.Interop.Excel.IRTDUpdateEvent
CallbackObject)
{
// GUI to show debug messages
output.write("ServerStart | " +
CallbackObject.HeartbeatInterval);

//Hold a reference to the callback object.
update_event = CallbackObject;

// does not work!
update_event.HeartbeatInterval = 500;
// HeartbeatInterval is still 15000

output.write(" update_event HeartbeatIntervalll: " +
update_event.HeartbeatInterval);

return 1; //SUCCESS
}


It seems that I cannot access the IRTDUpdateEvent.
Any ideas?

Thanks

Heribert