Hey Jørgen,
Thank you for your effort, and being so generous to share it with all of us.
This is very useful tool, but I think that there's a way not to lose that note information in the process of the converting.
Can I suggest an idea, if you allow me?
It's simple 'bulk' transpose on notes of my choice. Instead of setting their levels to 0, the notes would be simply transposed to the same type or their analog for my keyboard.
Example:
In some REVO Drums Kits Hi-Hats are on keys 13 to 22, that includes more than one versions of Closed, Pedal and Open Hi-Hats that can be subsequently divided and transposed on keys 42(closed), 44(pedal), 46(open) that will comply with any pre-Genos keyboards. Same rule could apply for extra Tom's, Snares, etc....per each REVO drum kit, since not all of them have the exact same drum mapping.
If I had the technical knowledge to write such software, I'll make it so it will allow me to describe each REVO Drum kit, transpose the notes to the ones of my choice, so I can later choose the closest sound-a-like drum kit for my keyboard.
I don't know how much of that is achievable with Java, but this is more or less my idea for improvement of such software as the one you've made.
Cheers!