samba - Jul 2003 - Samba + acl + Domain Admins

Hi!

I am running samba-2.2.7a with winbind and acl. I've setup share with 
default owner 'administrator' and group owner 'Domain Admins'
and let
access to others throw acl. Trouble is, when some user from 'Domain 
Admins' group changes some file, he also changes user and group owner to 
'his_username' and 'Domain Users'. I've checked smb.conf and
there is:

domain admin group admin users 
which means that no one has rights to change file ownerships.
What is wrong then?

Thanks