samba - Dec 2003 - samba-3.0.0-2 PDC + openldap - groups problem

Hi folks,

I'm having a hard time with groups when using samba as pdc. All my users
and groups are stored in ldap database and my linux doesn't have users
and/or groups. All the authentication is made by ldap.
When trying to put ?Domain Users? into Local group Power Users, I'm not
able to see the domain groups, I see just users.
>From windows xp workstation I checked another local group (Users) and I
see 3 different things:
- NT AUTHORITY\ Authenticated Users
- NT AUTHORITY\ Interactive
- S-1-5-21-3664164490-1896102861-1451414487-513 (which is my Domain
Users)

the last one I see just the SID with a '?' mark.

any idea how to fix it?

cheers,

sergio