10.4.11 Tiger Server as mailserver in Windows 2008 R2 domain (with AD)

1st post - please be nice...

I am wearing out my last good nerv trying to integrate a 10.4.11 server into an existing domain.

Scenario:

• Linksys Router with permenent internet IP and DHCP (say router IP is 192.168.3.254)
• Windows 2008 R2 Server as domain controller with AD (192.168.3.100)
• now I am adding the 10.4.11 server (192.168.3.2)
• a subdomain pointing to our permanent IP (mail.example.com)

The Mac should be mailserver only. The guy who set up the Windows server used example.local as active directory domain (like Microsoft unfortunately proposes).

I managed to integrate the Mac into the AD and all users and groups showed up in workgroup manager, but I could not turn on Mail for any of the users. Also I got errors when trying to add users or groups. In the previous installation I did not integrate the Mac into the AD and added users on the Tiger server manually and activating email was no issue.

Then I di some changes (don`t remember all of them) and now I can't even get back to that last state. I decided to start from scratch and make sure DNS services are good. I believe this is crucial to make the open directory service and Kerberos working and then lets me enable email for AD users... hopefully!

Is there anyone who can tell me which Tiger server services I need to configure and what exactly to enter into all DNS settings and the other required services?

I was following this guide on the Mac to join the AD: http://www.applesource.com.au/how-to/soa/Connect-a-Mac-to-Windows-Small-Business -Server/0,2000451082,339287478,00.htm

We only have a few users and I could add them manually without joining the AD, but anyway I need to make sure which services I need for a proper mailserver and I need correct settings for the DNS on the Mac.

Many thanks in advance...