Not sure how the Matsuda method would work in PokeMMO as the game is not regional, I mean sure you have different OTs but the regional difference is what makes the Matsuda method the best.
Scroll to the bottom of the Alphabet, it says "What Pokemon?" you can type in the name of the Pokemon you want, even if you haven't seen it. This is how people are asking for Pokemon that are either unobtainable, or haven't been completely confirmed to exist (i.e. Volcanion).
The code that is given to us by Archalias is not the source, it is complied Java/C++/Whatever Language, therefore even if you knew where in the code it was located, you wouldn't be able to change it without the source.