[Samba] samba 3.0, winbindd

[Christoph 2]

Hi,
finally i've managed to login with my windows-account on my samba server
using winbindd and pam_winbind.
butnow i've got a question:
if i login as "DOMAIN.username" login is working fine,
and in auth.log i get two messages from winbindd granting access for
DOMAIN.username ( i have set "." as Domainseperator)

but if i try to login as username without the domainpart,
i get an errormessage from login, saying the "user not known to the 
underlying authentication module" and in auth.log i get one line from
winbindd granting access for username,
and a second line from pam_unix saying "could not identify user from 
getpwnam(username)"

i've narowed it down to pam_winbindd failing on the account line in 
pam.d/login

is this intentional behavior of pam_winbindd / winbindd ?
Christoph