samba - Jan 2006 - Login domain set incorrectly once logged in with Samba 3 PDC

I have an NT4 machine joined to a domain with a Samba 3.0.14a-Debian
(standard install from Sarge) PDC.

Everything is appearing to work with the small issue that when I log
with a domain account, NT thinks that the domain is the netbios name of
the PDC rather than the domain name itself.

Instead of DOMAIN\david being logged in, PDC\david is. The problem with
this is that when I fire up say User Manager for domains, it tries to
find the PDC for the domain PDC rather than just connect.

Any ideas why this is happening?