Consider the following configuration section:

[htdocs]
  path = /srv/www
  valid users = +FERM
  write list = +FERM
  force user = webuser
  force group = www
  create mask = 0660
  directory mask = 0770
  browseable = No

This doesn't allow write access to anybody in FERM group, the share is 
considered to be read only by Samba 3.0.4.

Note: Samba 3.0.2a works fine with the same configuration.

For 3.0.4 to work one must add: "read only = No". Then the share is considered 
writeable. This contradicts the documentation, that states that "write list" 
directive should ignore the "read only" directive.

The "write list" DOES ignore the "read only" directive (i.e. works properly), 
if the directive "force user" is removed!

Regards,

Andrei Nazarenko