I did both and when I started it over the LAN it gives me the class menu I think, because when I press "c" it goes away and I press it again it comes back(It lists Nali, Pupae, Skaarj, etc. and a few buildings like a power building and the base).
I installed it using the umod, and then I opened USkaarj.bat and edited the prefrences like sound, video, connection, and controls. Then I want to Start New Multiplayer Game, checked out what the options were, chose seige and began it. I joined Team one and selected Skaarj and clicked Ready. On the other comp I started it up using uskaarj.bat and clicked on Find LAN games (after customising) and joined and selected team 2, and I think I tried to select NEG but it came out Skaarj so I mighta just hit Skaarj, then I hit ready then start match. Then I got the class menu.