Hi Faisal,
Saying frankly, we haven't tried to create users yet.
However, if you log on to the system and start transaction LDAP you will see Create button
Using it you can create different object classes
Based on the commands for assigning groups to users and synchronization I believe that GRC can produce request to LDAP for creating users.
Try to use Zoltan's document I provided you earlier or ask you AD admin to help with the command to be sure that you can create user through LDAP tcode. If it's ok, try to make it through GRC.
Regards,
Artem