While the accessory was obviously designed to be a game controller first, and a MIDI controller second, there is actually more functionality than expected.
Subsequently to uploading this video, I figured out what the button beside the touch controller is used for. If you hold the button while using the touch controller, the touch slider behaves as a ‘pitch? bend’ whereas without the button it works as modulation.
I also saw somewhere that the d-pad is used to split the keyboard, will mess? around with that some more.
See this earlier Rock Band 3 keytar post for more info.
Anyone else now rocking the keytar with a Rock Band 3 keyboard controller?