[Samba] grant windows group share permission

[lst_hoe02 at kwsoft.de]

Hello

i like to give a windows group (W2K3-AD) permissions to use a share  
read/write on a Samba domain member server. Therefore if have added  
the Samba server to the domain without problem and created a share  
like this:

[bild]
    comment = Some Comment
    path = /data/bild
    admin users = root
    force user = smbuser
    force group = sambashare
    valid users = DOMAIN\w-user1 @DOMAIN\w-group1
    guest ok = no
    read only = no
    writeable = yes
    browseable = yes

The windows domain user "w-user1" work as it should, but no member of  
the windows group "w-group1" can access the share. If have also tried  
mapping the windows group to the Unix group "sambashare" with  
"username map" but always get access denied eg. asked for a windows  
user.

Can please someone give a hint how to grant access for a windows group  
without adding/removing the members to a Unix group?

Many Thanks

Andi