In order to restore the AD information you need to follow a different procedure than that required for a normal restore, check out :
How to perform a non-authoritative restore of the System State - http://seer.support.veritas.com/docs/236661.htm
Performing Authoritative Restores of the Active Directory to a Windows 2000-based domain controller. - http://seer.support.veritas.com/docs/235160.htm
Which of these is more relevant will depend on how your network is setup, and which information you need to restore, but unless you have more than one AD server it will be the Authoritative restore.