The Jaguar source code is available from TI (at least for now):
http://www.ti.com/tool/rdk-bdc24-cd. More details in
this thread.
I have to ask, though - Why isn't the built-in encoder input sufficient?
Also, be aware that last year it wasn't legal to use custom Jaguar firmware,
per [R61]. I would be surprised if that changes this year.