[Samba] local users in domain member security.

[Meli Marco]

Hi,
I have samba 3.0.7 installed and it works fine in security=domain with
domain user accounts, ACL and so on but now we would like to add some users
in local database account (/etc/passwd & /etc/smbpasswd file I though, so
they are few users).
I try to use "smbclient /server/data -Ulocal_linux_user_name%password" to
test it's everithing ok, but I always receive the same error:
session setup failed: NT_STATUS_LOGON_FAILURE, I presume that it try to find
the user in the domain, but I have configure nsswitch to search in files
before and winbind after.
What's wrong?
Thanks a lot.
Marco.