I've talked with the IT guys at my site, and they're willing to pose the patch to the people in charge of the exchange servers at the corporate end. Local guys were aware of the patch not being on, and as far as they know (as they have Vista machines on the corporate network) Vista is *not* an unapproved OS.

They think that the IT crew in the corporate server houses were waiting to see how many employees were adopting Vista at home before applying the patch. (If it ain't broke, don't fix it.)