Exchange over Mac Entourage - Auto-Reply Infinite Recursion Loop!!!

I have a Mac client running OS/X with "Entourage" over Exchange. The user is out of the country and set up his auto-reply and everything was fine until today. His assistant has delegated authority to his mail box (Owner - permissions) in her MS Office Outlook. She checked his mail this afternoon and found that there were 119,000 unread e-mails in his Inbox and the number was climbing.

A message had been sent to an associate who also had their auto-reply configured or possibly the client's own e-mail address was used in a group mailing (I am not sure of the exact details because I am off site right now) and a recursive-loop started.

I had her stop the auto-reply which stopped the flood. Now it is a matter of separating single, necessary e-mails from the deluge of "Out of Office" auto-replies that have flooded in.

I had believed that Exchange was configured by default with safeguards against such a loop.

The network is running SBS 2003 (fully service packed) w/ Exchange 2003 (SP2).

Is there a manual setting I can configure to stop this from happening again?

Does anyone know if this is due to the Entourage application (painful to work with over Exchange at the best of times)?

The worst is over but I would like to avoid it again. Can't find much on the settings yet but still looking...

Any pointers or links would be appreciated.

Thanks.
-MP