samba - Jun 2004 - Keep existing domain afterinstalling a new server?

Hi,

I have still a RedHat 8.0 server with samba-2.2.7-5.8.0 as PDC.
We have about 60 users and workstations.
Now I have to install a new server with RedHat ES 3 and samba3.
How can I port the domain to the new server, so that I don't have to add 
every user and workstation again?
And we also have roaming profiles, which I have to keep.

Thanks!

Nicole