Debugging a Hierarchy user exit ZXRSAU04

Guys,

We have added custom code to the hierarchy user exit ZXRSAU04. I am trying to debug it by right clicking the datapacket and then doing a simulate update. I am getting the message "simulated hierarchies cannot be edited". I added an endless loop in the exit ZXRSAU04 and then loaded a hierarchy. It didn't stop there. If anyone has debugged a hierarchy user exit, please let me know the steps for debugging it. We are on BW version 3.1c.

Thanks,

SSB.