I would just add that if this is working for some users but not other users, then there's something causing the difference between the users.
The primary gid and other attributes like the home directory and the shell should still be manageable in Express.
Please make sure the following parameters are in your /etc/centrifydc/centrifydc.conf file and uncommented:
auto.schema.private.group: false
auto.schema.primary.gid: <gid> where <gid> is the gid of the primary group your users should have.
After making these changes run "adreload" and "adflush -f". At this point all of your AD users should have a primary group of <gid>.
Regards,