Why would you want to wire a Sony Wreless IR remote to the Empeg via the Tuner module?

If you install the famous Mark Lord Hijack kernel with inbuilt IR mapping (amoungst its many features) then, provided the Sony RMX5S wireless remote's Ir transmitter is compatible with the IR receiver in the Empeg (which I am not sure about) then you can easily map [and re-map] the codes the various buttons on the Sony wireless remote send to perform whatever functions on the Rio or Kenwood remotes you like.

You can easily find out if the RMX5S is compatible by installing the latest Hijack kernel then going to the Buttons Codes display function in the kernel [push and hold the knob on the empeg in, once the hijack kernel is displayed to get the main hijack menu, and select the 'Button Codes Display' menu option (press the knob once to select)].

then simply activate the buttons and controls on the Sony wireless remote and see if any codes are being reported - if so, then a map will be possible.

If nothing is displayed then the Sony wireless remote is probably not comaptible and would have to be hardwired
via the Tuner or via special IR receiver device such as a small microprocesor e.g. a PIC micro - then you would still have to pretend to the Tuner unit that you were a wired remote...

Either way, if you do this can you report your findings as this information will be useful for the FAQ.
If you get a list of button codes, then someone will be able to help you build the mappings needed to make the Sony IR remote work however you wish with the Empeg.