Hi,
That is most likely because you don't have the Exchange management tools on the domain controller.
If you open Active Directory Users and Computers on the Exchange server you will see the extensions.
Cheers
Nathan
Nathan Winters - MVP Exchange Server
MCSE & MCSA 2000 & 2003 + Messaging, MCITP Exchange 2007, MCP, VMWare VCP v2 & v3.
Welcome to the Microsoft Messaging and Mobility User Group: http://www.mmmug.co.uk