BTW, it's a Sony RM-X117 remote

When I do a search on "RM-X117", Get the following information:

High band Wireless Card and Rotary Commander
High Band Wireless Commanders use High Frequency Control Signals that bounce off the interior of the car to access the tuner.

That means uses a high frequency band instead of the standard consumer IR band. Therefore it cannot be seen by the empeg player as stated here. It just won't work.



Actually I'll be using an SWI-X unit to get the steering wheel controls to work, but it should be the same thing (I want the empeg to react to the SWI-X output when it's emulating the Sony head unit remote buttons).

No, the SWI-X is not the same thing. The SWI-X will work, the RM-X117 will not. The SWI-X will broadcast at the correct consumer IR frequencies. You will "teach" the SWI-X by using the Rio remote, not the Sony remote.