I looked into this approach a while back and came to the conclusion that it really wasn't worth the effort. On the hardware side of things due to the power levels you're dealing with the IR performance really won't be all that great (depending on the hardware you mockup your distance/range can be up to a few feet, assuming all is perfect), but the software side of things is more complex as you have to actually cheat and produce sound waves that mix both channels in order to generate the appropriate signal. So that is, it's not as easy as just "Recording" and IR signal and playing it back, you have to specifically generate the signals to match with the audio output capabilities of the tablet's sound hardware; I'll have to look into it again now that I have some time available, but last time I asked about this I got no response from anyone on the software side of things...

Thanks,
-Rob