Catching button click event in VS addin

I am trying to catch the Load test run button click event in an Addin I'm writing for vs2010

I've tried a couple of approaches in the OnConnection event

 var evt = _applicationObject.Events.get_CommandEvents("{7A368D2D-B70C-45EE-9854-D72059FCC7E3}", 8192);
  evt.BeforeExecute += new _dispCommandEvents_BeforeExecuteEventHandler(CommandEvents_BeforeExecute);

The event is caught only after I open the Addin manager uncheck the adding close the manager , enter again and check the Add in again

Any idea why this happens?