Jabber, Xserve And File Transfer In a Dmz


I have an XServe connected to a Linksys router which is sitting in the DMZ. I am using Jabber to connect from inside and outside the network for chat. Using GAIM as a client for Windows and iChat AV as a client for MacOS. Can do File Transfer through Chat client inside the network to windows as well as Mac but cant do it outside due to the DMZ. Anyway that I can get around this?

Much Thanks in advance.