samba - May 2010 - Upgrading the Samba installation on an OS X 10.5 server?

Hello Samba folks,

I have an OS X 10.5 server that I would like to use to run as a PDC for some
Windows 7 computers. The current Samba installation (3.0) does not work, and
according to the Samba wiki I will need version 3.3 or 3.4. I would like to get
the new version of Samba running; however, I am concerned whether or not doing
so will work with the Open Directory authentication system in 10.5, and whether
or not there will be incompatibilities with Apple's Server Admin tools.

Has anyone successfully installed an updated Samba installation on 10.5 server?
I found a single thread on the Apple discussions regarding the exact same issue
I am having
(http://discussions.apple.com/thread.jspa?messageID=11224478&#11224478), but
I do not want to resort to using Windows 2003/2008 server.

If anyone has a step-by-step, that would be fantastic.

Thanks a bunch,
-Topher