Xolox offers no "forceIP" options, it tells the private network address (LAN) instead of the real internet IP.
So you can only serve gnutella push requests, these do ONLY work if the opponent has no firewall and/or can accept incoming connections. According to the limwire gnutella network statistics only a few percent of the clients can accept incoming connections (you can't eighther at the moment). Just watch your gnutella servant a while, for sure there are people downloading from you! Do you share enough files?
Meanwhile.... if you have access on the computer with the real internet IP, run a socks proxy and connect Xolox to that proxy service.
Hope it helps, Moak