Go here:
http://www.project1999.org/forums/forumdisplay.php?f=25
New thread, select IP exemption as the prefix.
BRIEFLY explain you have a roommate you want to lan with.
Give the ip address and login names of both accounts in the message field.
Post, wait. Do not bump the thread. It may take a few days. May take minutes.
Anyway just be patient. They don't want ingame petitions or pm's about this. They'll pretty much 100% accept it unless you were caught boxing in the past or something.