What I think I'll need to create is some completely different drum styles. so I guess my questions is whether or not the only way to create the drum parts is by modifying the already existing audio files for drums found within the Audya.

If this is the only way it may be a problem because I don't know how you can modify an audio, unless it'd turn possible to simply transfer complete audio recordings of drums playing to make them the drum part of a style then add different files for variations and fills. That would be great indeed.

I did it once a bit with my Casio by writing the midi for each part on my computer then transferring it to the keyboard but I'm not sure how it works on the Audya, since, again, the drums are not played by midi.