David,
The installation for the Symantec Mail Security for Microsoft Exchange (on 64bit) requires the free download and installation of "Microsoft Exchange Server Mapi Client and Collaboration Data Objects 1.2.1" which I am guessing is becasue the MAPI stuff is missing in that version of server/exchange. I wonder if just having this installed would solve the issue of needing Outlook 2007 installed on the server?
Anyone else know?