samba - Feb 2013 - Share permission problem

I have a samba 3.5.6 joined to my samba AD.

I set this share:


[Nodo$]
        path = /media/almacen/Admin/Windows/
        read only = yes
        valid users = @EPEPM + epepm_nodo

>From Windows XP only users from this group epepm_nodo are allowed. But
when I try from Windows 7 any user is granted access to this share.

Any help will be really appreciated.

Felix.