[Samba] Need urgent help with "user_info->client_domain.str" and "user_info->domain.str"

[Dirk Brenckmann]

Hi there,

anybody here to help me with:
"user_info->client_domain.str" and "user_info->domain.str"

Problem:
check_ntlm_password:  Checking password for unmapped user 
  [FRSTPRV.DE]\[SambaAdmin302]@[HEARTOFGOLD] 
  with the new password interface
check_ntlm_password:  mapped user is: 
  [FRSTPRV]\[SambaAdmin302]@[HEARTOFGOLD]

Where from does samba receive the "user_info->domain.str" ???

It ([FRSTPRV]) is definitly wrong, and I'd like to know where (in 
the code) and how "user_info->domain.str" is resolved/set.

I'm running Samba 3.0.2a and can't join Win2K/XP/whatever to
the samba PDC of [FRSTPRV.DE] because of this...

...switching  [FRSTPRV.DE] to [FOO] does not change
a thing ;-)

...and yes - there is a Samba 2.2.8 Domain in the net, using the
name "FRSTPRV".

Any idea what's going on here?
Thanx 4 any help
Dirk Brenckmann

P.S: Already found:
       http://samba.org/doxygen/samba/auth_8c-source.html#l00205
       (But does not "really" help without more context...)