Have you tried using the Yamaha MIDI mapping in EZdrummer 2:s settings page? Further - many e-drums can be MIDI re-mapped, and it's also possible to map incoming MIDI in many DAW:s.
Superior Drummer 2 is the bigger brother of EZdrummer 2, and has all the features required for a complete custom MIDI mapping.
We are aware of that there are features in Superior Drummer 2 that some users would like to see in EZdrummer 2, but we have to draw the line somewhere - to be able to call EZdrummer "EZ". I can't comment on future updates and releases, but we are listening to our customers and are always trying to make the most of you satisfied!