samba - Jul 2002 - Unasked-for ACL/Unix ownership changes with XFS?

I'm having a problem with Unix ACLs.  It took a while before it became
apparent, but, clearly, this can't be the way ACLs are supposed to work.
If I have a file, "file", and it's owned by "user", but
rwx ACLs are
granted to "foo" and "bar", everything works fine... until
(say) "foo"
writes to the file.  Once that happens, user gets "popped" off the
stack,
and foo becomes the Unix owner of the file, but "loses" the ACL
permissions.  If, then, bar writes to the file, foo goes away, no ACLs are
left at all, and bar is the Unix owner with rwx permissions.  This is
under a Samba client, running in a Samba PDC environment, with 2.2.4 on
the PDC and 2.2.5 on the server.  The filesystem is XFS, running under
2.4.18, downloaded as of March or so.

Any ideas/hints/suggestions/etc.?

Thanks!

-Ken

P.S.  If anyone has a fully-functional smb.conf with ACL support under XFS
that they'd like to share, please feel free to mail it to me directly.