DHCPv6 question

Fellow list members,

I have a kind of mixed mode network at home w.r.t IPv4 and IPv6. I run an
IPv4 DHCP server on an Ubuntu server. IPv6 functions in my network just by
the automatic stateless configuration. Now I found out that Vista and W7
clients in my network do not get an IPv6 DNSserver addres assigned and
consequently cannot resolve hosts in my network. Quite logical, since the
DHCP server only assignes v4 stuff. I wonder if it would just  work when I
switch on just the DHCPv6 server in Monowall. If the Windows clients only
get a DNS server, that would be enough for the moment. 

My only alternative is to install the latest ISC DHCP server (not packaged
for Ubuntu...) from source, which can do v4 or v6 (but not at the same time)
alongside the existing v4 DHCP server. Sound like a rather tricky setup.

Any suggestions how to give the Vista and W7 cleints an v6 DNS server
address?

TIA
Egbert Jan (NL)