[Samba] Group sharing between NT and Linux domains

[Carl J. Hilinski]

I need a little better information regarding the mapping of groups
between an NT PDC and a SAMBA PDC, which trust each other. 
 
On the NT machine is a group called "ntgreen." On the Linux box (running
RH9 with Samba 3.0), there is a group called "lxgreen".
 
I've done a: net groupmap add ntgroup=ntgreen unixgroup=lxgreen. The
mapping shows up in a net groupmap list.
 
However, when a member of the ntgreen group logs in on the NTPDC and
attempts to access a share in the SAMBA-controlled domain that is
supposed to be restricted to the lxgreen group, access is denied. The
user can access shares that are open to all users.
 
I am obviously missing something here.