[Samba] Permissions "Owner and Group"

[cajaudec at col3.telecom.com.co]

Hi, I'm having this problem..
Every time I modify a file from a Windows Machine, UID and GID of the file changes.
By example the file foo.
before (This ones are what I want to preserve)...

foo    rwxrw-rw-    beforuser   beforgroup

After modificacion (With Word or Excel by Example or any other software)

foo    rw-rw-r-x    afteruser     aftergroup

It's mean "foo" changes his user-owner, group-owner and permissions.
What I really wants is that files always can preserve his (users and groups)
owners. I want files that even when users modify his content doesn't change
his attributes or owners.
Thank You.
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