I am not absolutely certain (and that universal remote link probably means the rest of this is "wrong"), but from what I read yesterday, it seemed like the "433 MHz" transmitter/receiver combo the TouchTunes jukebox uses isn't a "standard" 433 MHz part; its frequency is "off" by so many KHz that prevents you from using off-the-shelf transmitters/receivers to make such a remote control.
I didn't research it in any great depth, though, and like I said, that universal remote link says something completely different; but then again, the lack of sites and discussion out there about homebrewing such a system (though there are many people asking about it; just no answers) seems to say that to do so will be a difficult proposition.
You might be able to do it if you modded one of those 433 MHz receivers and transmitters to run at the exact frequency of the jukebox (which would require more than a few extra tools most people don't have - frequency counters and signal generators, for instance); then again, maybe I was reading too much into what little I could find, and the frequency is standard...
