I had a really good day at work and I'm feeling flush, so I bought S1 Artist.
Now I see your problem.
I searched the S1 Forums and it seems most of the folks over there are KB players.
The few who've tried to use MIDI with Amplitube have mostly failed.
Except the one guy who said "It's really quite simple..."
He went on to explain pretty much what your screenshot showed.
It doesn't work.
I posted a request for help with a screenshot and quoted the guy's post.
We'll see if we get a solution.
Did I mention how much I hate S1?
Between you and me we've spent dozens (hundreds?) of hours trying to do what takes less than 2 minutes to set up in any other DAW.