How to setup a os x router as a ODM?

I have a OS X 10.5 server setup as a router/firewall at home and now I want to add a OD. But when I promote the server to ODM it goes on the info that it gets from en0 and that is the WAN-info. Therefore Kerberos fails. How do I get the promotion to look for its info on en1 that is the LAN. There I have DHCP, DNS and all that setup and working. Feels like it should be a simple cli-command or something but so far I havn't been able to track it down. So does anyone know what I should do?