The default behaviour for Samba is to have files created by guests have the nobody:nogroup ownership. However, for usershares, particularly those created by certain user interfaces like nautilus-share, this results in files that are not owned by the user in the share, and hence cannot be manipulated either.
I'd like to propose that the net usershare utility be given an inherit_owner=[y/n] option similar to the guest_ok option that already exists in order for this purpose.
We want the usershares to be as simple as possible for security reasons. Thus we don't really want to add many more fancy features to the usershare parser.
Please use a "usershare template share" to add the features you want to your usershares.