IrDA and the RCX

Does anyone here have any input on how to get a Zaurus SL-5600 PDA's IR port
to engage in two-way conversation with an RCX? Ideally, I'd like to get the
IrDA port to behave exactly as the USB tower does with Lejos.
The goal is to get the WiFi enabled Zaurus to convert an RCX rover into a
remote-controlled rover, by placing the PDA on the physical construction and
allowing people to control it via a java interface remotely. While this
works in theory with an anchored USB tower, the 6m range is virtually
useless for any practical application, and so I am looking in to ways to get
the remote control to extend beyond the 6m range, hopefully up to the WiFi
range.
Again, any input would be appreciated. Thanks.