How to change IP address of Mac OS X Server

I'm having problems testing a netboot server, because I need to change its IP address (at least, how it obtains it's IP) Doing it in the System Preferences pane sort've works (for basic TCP services) but screws up all the server daemons. I think it may be a problem in not properly updating a particular file with the new IP info (/var/db/System Preferences/preferences.xml) but I'm not sure. Any ideas??