Exchange in Mail is sometimes in a sync loop

It sounds exactly like the problem we have. I tried to "refresh" the mailbox by exporting all items from contacts, calender, inbox and sent, killing the box ++ setting up a new one (at the exch server (2k7sp2)), connecting back(1st Mac mail then Outlook 2k7) completely killing mbox settings at Mac mail and creating a new account profile ++ restore the items back to the mbox (using Outlook). It worked for half a day but after returning home and connecting from a different network the promblem turned back. - Now we know, it's not connected with illegal Structures or structural problems / inconsistencies somwhere inside the mailbox storage.

But still no help with the problem itself.