Not sure if this will help, but I use the midi Monitor app on the iPad to figure out how midi instruments are configured. This will show the raw midi codes for every action that puts something on the midi bus.
Here is what I found.
1. The keys seem to work fine, even with Sample Tank.
2. The Registration keys cause the monitor app to crash, not sure what is up there.
3. The two left encoder knobs seem to be on the same channel, which is odd. The right one doesn't return anything.
4. Pedals, pitch bend, and mod wheels work as expected.
Hope that is helpful.