[Samba] Need help with "username map"

[bdehn at oreillyauto.com]

We have setup a Samba member server using Winbind (3.0.14a and NT4). I am 
trying to "map" the NT Domain ids to root  (root = admin administrator 
rdehn) but this seems to be ignored when I try and connect to a share. The 
"username map = /etc/samba/smbusers" line is in the Global section of 
smb.conf and testparm is OK. What am I missing? Is this not possible?

Thanks in advance for any help / suggestions!

Bob Dehn