By the way a little bit of Information. Did you know that Office 2011 for the Mac does not support Online Archive Mailboxes!!! DOH!!! Why Microsoft didn’t add this in I dont know.
Here’s the official word from Microsoft on the subject :
Outlook 2011 for Mac (formerly known as Entourage) and previous versions of the Mac client do not include support for accessing the online archive mailbox. However the Mac Business group is looking at supporting this with a future update but there’s no confirmation or time line though.