[Samba] giving user rights to files

[Valéry Roché]

Hi list,

I have a Samba 3.0.22 server working as domain controller. When a user 
copy a file to a share, the file is owned by user root and group "no 
group" , not by the user and its group.
All the users are in an LDAP directory, authentication works good, all 
groups are declared in LDAP too.

What should I do to have the file with the right owner/group membership ?

For groups, I maybe have to use the group map command. But for users ?

Thanks for any answer you could give me,
Valéry Roché