If you're going to be moving a bunch of users, the best thing to do is to take the Unity server off line, move them all and then bring the Unity server back up.
there's nothing special you need to do on Unity to "point" us as the right mailstores sine we query the Exchange directory for the users' mailbox and IT always knows where that user is homed and we get a handle to the right mailstore.
If you don't take Unity off line, however, we will keep that handle to the old mailstore open which screws us AND Exchange up... you don't want to do that. You can move individual users one at a time by logging them out of in DOHPorpTest but if you're moving large numbers of users, it's always best to take Unity all the way off line while you do that.
Jeff Lindborg
Unity Product Architect/Answer Monkey
Cisco Systems
jlindborg@activevoice.com
http://www.AnswerMonkey.net (new page for Unity support tools and scripts)