[Samba] Group Mapping: All Users from a Domain group should be able to write to a local group

[Bingo Tuk]

Hello Mailinglist,

I have created a local user "localuser" who is in the local group
"localgroup"

$ id
uid=1001(localuser) gid=1001(localgroup) groups=1001(localgroup)

My machine authenticates against Active Directory - works

The AD-User "aduser" belongs to a domain group "adgroup"
$ id
uid=6161(aduser) gid=5513(domänen-benutzer)
groups=5513(domänen-benutzer),10656(adgroup)

I have mapped the local group and the adgroup with the command
net groupmap add ntgroup="adgroup" unixgroup=localgroup rid=10656 type=d

That works also
# net groupmap list
adgroup (S-1-5-21-000098831-0000488756-4286701815-10656) -> localgroup

Anyway, the user "aduser" can't write a file with the group "localgroup"

What am I missing? Any hints?

Thank you very much