How much will the add-on cost? Or is it going to be a free download for those who bought the original?
I'm not really a solo player, so if it's not possible to play T-72 online somehow, I'd give it a skip until the multiplayer add-on is available then buy the whole bundle in one go.
I don't know much about game programming, but given that a LAN uses TCP/IP, and the internet uses TCP/IP, why isn't direct mode somehow available? Lag wise, considering most people are on broadband anyway, at least a bodgy version which only works for broadband people and not 56K would be much appreciated...