[Rey_a]

No tablet probably works the same way as the computer. I was more thinking about the instrument side.

If the commands you are trying to get across from the tablet are the same as the ones that are working when sent from the computer, using the same cable, I guess they should also work from the tablet.
In my case I remember from Roland Atelier, that the USB midi connector will only send information about the keys that are depressed and released, but no program changes and such. Furthermore it will not respond at all to MIDI commands received . . . .

To help debugging . . .
After connecting the cable on the tablet and launching MS Pro, do you get a message asking if the USB connection can be used by MS Pro ?
I know Tyros had a display that shows a led light up whenever MIDI commands are received. It does not show what commands but it helps confirming that commands are beeing received . . .