[Samba] Mapping Windows groups to Unix ones on Samba 2.2

[Dr. Matthias Schlett (987)]

In my opinion the net groupmap doesn't help you.
After applying it to all my existing unix groups the right windows group names
are shown, but the groupmembership is checked against the unix groups.
Putting a user into a windows group is not enough, you have to put it also
into the corresponding unix group.
Several days I try to understand, how the mapping of users and groups between unix and
windows works. The more I'm reading the more confusing it is.
We have :
- username map
- net groupmap
- idmap for uid  and  gid
- wbinfo to show or manipulate mappings

Who can explain the differences ?

Regards
M.Schlett