[Samba] Directories and group permissions

[ljerem at fi.uba.ar]

Hi all. I'm having troubles with directory permissions. We migrated from
PC-Netlink last weekend and today is Samba's second day in production.
It's a Samba 3.0.13 installed from an rpm package, running over a standard
Suse SLES 9.
I set the permissions over a directory using my XP workstation (right
click over the directory, properties, security). I add the group and give
it the permissions I want (Full control or no access... pretty standard).
The problem is that after a while, I go to the security tab again and the
permissions I gave it are gone. However, the changes seems to take efect
(in some cases...).
Is it that I need something else (file system side) to work with Windows
ACL's (NT ACL's... again, the standard)?
I decided to manage file and directory permissions at the file system
level, but with standard unix permissions I can't give just two (and only
two) independant groups write access to the same directory, right?
Is there something I can change in the smb.conf file to support this
behavior?


Thanks,
Sebastian