ACL's on SAMBA file server

[George]

I have a Samba 3.5 server running on Ubuntu 10.10
I'm have it the server on my Windows 2003 Domain but am having trouble 
setting up the ACL's.
I can set some of my ACL's for users but it doesn't alwasy stick and 
apparently giving a user the modify right automatically gives them Full 
user rigths. This is probably related but it refuses to let me give any 
of my domain users any access rights to files or directories.

Has anyone seen this or have any ideas how to solve my ACL problem?