Of course it'd be simple. But there is no way of contacting the developer, as it was (probably) just the SuperCard team using a fake name with no contact details so that they couldn't be held legally responsible for not releasing source, which they should have because it used GPL code.seems like it would be a fairly simple addition for whoever coded the emulator in the first place, since it can already map A and B to X and Y, it'd be great to have the possibility to remap all buttons. perhaps someone should into contacting the developer(s) [?]
Why would they not want to release the source? I'm sure that if there was enough demand for it they'd release it since a better GBA emulator just means more reason to buy a DSTWO.