[Samba] winbind and useradd

[Gabriele]

Hi,
I have succesfully installed the latest version of samba (2.2.7a.tar.gz) 
with winbind support and
it seems to work. If I run getent passwd or group I can see local and 
remote (NT4)
users and groups but,  if I create a new user linux login with a NT group, 
useradd says:
[linux] useradd -g DOMAIN+group -d HOME DIR -s /bin/false  USER
useradd:unknown group DOMAIN+group
It not should use nsswitch.conf to check for groups?
My nsswitch.conf file is:
passwd     files winbind
group        files winbind
With getent it works but useradd  not!

I saw also in /etc/pam.d/ there is a useradd configuration file, so I tried 
with several combinations
to add pam_winbind.so module but without success.
useradd file.

I have not any ideas for solving this problem. Can anyone help me?

Thank you very much for yours collaboration,
						Gabriele.