Also, if you haven't seen one, I took a look at one today. The thing is much bigger than I think you'd expect - it's like a baby leg. I would guess it's dimensions at about 2" square at the base, tapering to a 3/4" point about 7" out. It's huge! Is the XM4S that size, or is it smaller?

Leave it to Sony to muck with IR - like you need a much faster IR interface for button presses. This is typical though - they did something similar on their 'high' end home audio gear - the ES series were infamous for using 2-way IR that only worked with their own remotes and couldn't be programmed into a proper learning remote.

Whatever you do, don't try figuring it out - that would violate the DMCA and they'd have to incarcerate you as a pirate and terrorist.