No Shutdown After Client-Backup

I want to shut down the computer after the client backup is done. I created a sheduled task at the client computer. This task calls a batch file to shutdown the computer
The task is triggered by the event 769 which should be sent by the WHS after the bckup is ready. This worked perfect with WHS V1. I now switched to WHS 2011 and the task is not started. The backup is marked as successfull in the WHS dashboard but I don't find any event in the client and the client didn't shut down.
Is there anything different with WHS 2011?

Thanks in advance for your help
computerschrat