The common case is that a user wants to send out from a supercontrol. That's possible by using "Supercontrols Send Own Values" option, but it's not recommended. HOWEVER, THAT'S NOT THIS CASE. There is no way to have MD send out data that it receives, which APPEARS to be the case you're describing (though I might've missed something). So, anyway, the goal is to NOT use the same CCs on the Blueboard as you use on your MIDI target (amplitube)... that way you can switch pages and control something else (if you want).
If I understand correctly, you'll need to adjust your mapping for this scenario and add 4 subcontrols. And remap Amplitube.
On the other hand, if you want to do pure MIDI conversion, a dedicated app like MidiBridge or MidiFlow will do what you need, but this isn't really conversion, I think, so... anyway, hope you get up and running without much difficulty.
A third option is to talk to IK Multimedia and ask them to change the Blueboard. Having the Blueboard send momentary data would be great... while you can make a toggle from a momentary, you cannot make a momentary from a toggle, so improving the Blueboard is a way to help everybody.
Thanks!
Dan