TAC actually gets a fair amount of cases on this. For some reason folks like to build these machine away from the customer network and assume that if the domain controller and domain name match up that the Windows components of the Unity server will never know the difference. The truth is that in Windows domains the machine name means very little. It's all about the Security ID or ‘SID’. Each machine gets its own SID which is unique to that system. If Windows only cared about machine name, the domain would be very insecure.
What you are trying has never been tested and is not a supported operation. If things break, TAC is more or less going to tell you to reinstall. I have setup a Unity 3.0 machine at my desk so that all I had left to do was add it to the domain and run Configuration Setup. That worked fine but once again not an officially supported way of doing things.
With that said, as long as you don't have Exchange or AD on the machine you should in theory be able to make it a member of the new domain and re-run Configuration Setup. If you put Exchange or AD on the box I doubt you can pull it off.
Also, we are working on making setup a lot cleaner but that project is still a long ways off.
Good luck. :)
Keith
Keith Chambers
Unity Technical Lead
Unified Voice Team, San Jose
Cisco Systems
kechambe@cisco.com
