Samba PDC with VPN access

[Jon Theil Nielsen]

We have a Samba PDC on FreeBSD 7.0-release. The goal is to make users home
drrives accessible throuth a VPN connection from Windows clients. Until now
I have experimented with the Poptop server without much success and now have
a working configuration based on Mpd4. This is not ideal, since I have to
keep usernames/passwords manually updated in the mpd.secret file. And that
can not be combined with users changing their own Samba and UNIX passwords
via password sync.
It seems that some kind of authentication via Winbind and ntml_auth would be
a way to go.
Maybe it can be done by installing a Radius server to communicate with Mpd,
but that seems to be unnessesarily complicated.
Does anyone know the "best" solution to achieve the goal?

Regards,
Jon Theil Nielsen