[Samba] samba in a WAN

[ODien]

Hello...

We have a NT4 Domain in our mainoffice.
Now we have to install servers all over germany. 
(About 20 locations) The offices are connectet over DSL/VPN.

We think about using samba to have a stable and inexpensive solution.

Is there a solution to use samba over a wide area network?
We have alraedy one standalone samba-domain (domain-logons with
machine-accounts) in a small office in Berlin.
It works fine and makes no Problems.

What kind of problems we have to face, if we want to install samba servers
connectet only over DSL/VPN to the "mother" in our mainoffice.
Whats about:
- authentication
- broken connections to the domain
- single point of administration
- login scripts
- dhcp/dns

we are working at this time with MS. So we have not the best practice in
Linux/samba. We have to learn a lot. (also english:-))

Have fun and thanks....
O. Dien