Creating and assigning a mandatory profile to a user is incredibly easy, but I am often surprised how many times people do it the wrong way.

http://support.microsoft.com/kb/307800

This page is a great resource for people creating a mandatory profile for the first time and need help. Key things to keep in mind:
1. Configure the profile the way you want it BEFORE you do the system copy.
2. When doing the system copy, make sure you set permissions so EVERYONE that needs access to the profile will have it.
3. Change the ntuser.dat to ntuser .man AFTER the system copy is complete.