No matter how many times I’ve done this, I can’t seem to remember how when I need to do it again, so here it is. When the Admin pack is installed on a workstation, the AD users and computers MMC does not include the exchange tools plugin. This means that you don’t see the Exchange tabs on user object properties in Active Directory. You can download the admin tools from http://support.microsoft.com/kb/304718 . After that you could install the Exchange management tools from the Exchange CD…or you could just get the piece that you’re looking for by doing the following:
From the Exchange 2003 server in ‘\Program Files\ExchSrvr\Bin’ copy the following to your local system32.
cd to \program files\exchsrvr\bin
regsvr32 /i maildsmx.dll