[Samba] WINS name resolution doesn't work

[kissg]

I've set up my Samba PDC to act as a WINS server, because I need remote
access to it (through a VPN connection). I put "wins support = Yes" into the
smb.conf file. As far as I know, WINS doesn't use a unique port number, so
enabling the usual NetBIOS ports (137/udp, 138/udp, 139/tcp) on the firewall
should be enough to make WINS work. I did this already.
I tried to connect to a share on my PDC through a VPN connection. My VPN
server properly sends the address of the WINS server, that's sure, I can see
the correct address in the output of "ipconfig /all". smdb and nmdb are
bound to the wildcard address to accept connections from ppp interfaces
created on the fly. Everything seems to work correctly, but my clients
cannot use NetBIOS names, when connecting to a share. Connecting to the
server by its IP address works with no problem.
I am creative, so I decided to disable WINS and use DNS instead. After that,
name resolution worked wonderfully.
But it's not that easy... by using DNS, my PDC is not able to resolve the
netbios names of remote clients, because they don't register their names in
DNS when connecting. Is there any way to use WINS on VPN clients? It seems,
that Windows silently ignores my WINS server and only tries to resolve names
with broadcasting, which is of course not possible through a PPP connection.
Do you have any ideas?

I use Samba 3.0.28a on my PDC and Windows XP Professional on my client.