samba4 - acces to shared directory by groups permissions don't work

[Justo Alonso]

Hi !
    I'm trying to configure a shared directory and set permissions by
groups, but doesn't work.

    On windows, I set write access to "Domain Users" and the user of
the domain can't write on the directory. The unix group is created
with the same name.

    I read about "unixname" and map domain to unix group with swat,
but I don't known how make it (swat don't work on samba4 > alpha3,
isn't it?)

    How do I have to define permissions in Windows and Unix to make it work?

thanks in advance

justo