I have just started testing OCS 2007 on a virtual environment. The funny thing, everything looked ok, but when I run Active Directory Users and Computers, there was no Communications tab under user’s properties.

It turns out, if you are running a 64 bit environment (which I was, as I have AD and Exchange 2007 running on the single box), you need a different command line to run ADUC.

Here is the article from microsoft.com forums:

"Office Communications Server 2007 will only ship a 32-bit version and will only run on 64-bit machines in WOW32 emulation.

To use Active Directory Users and Computers (ADUC) on a 64-bit server that you have installed OCS 2007 or the OCS 2007 Administrative Tools, you will need to open ADUC by typing mmc -32 dsa.msc