the shuttle was midi command. The unit comes with a mapping software that export a file that you can import in Nuendo if I remember right that assign the wheel, shuttle, encoder, push buttons etc… to function via midi or HUI or Mackie protocol (you could choose I think). There were several options, and depending on the protocol you have a few changes in the assignment because of addressing function. You could also assign function to the encoders via the midi panel in Nuendo. I red a lot about midi back then, I forgot most 
I remember that it was a good and proper build from people who did think about what producers need. You can actually also mail the guys, what I did, they were very kind and did answer fast. But for me, midi was not good enough, so I switched to eucon.