[Samba] ACL not working

[Adi Nugraha]

Hi

I want to set Security to single file, but I keep getting access denied, I
can change the Permissions that is alreday displayed, but I can add any user
or group, after redaing the samba how to it seems I need POSIX ACL, but the
book didn't mention anything about how to use POSIX ACL, Trying to set it
from windows doesn't work, can anyone point me to document about POSIX ACL ?
BTW I'm using mandrake 10.0 and samba with ldap backend

thanks