I'll try to setup my computer later, I haven't used DCS since January.
Let's try a different approach. In the controls settings, go to the OFF cell, and bind the virtual buttons you have defined JOY_BTN33 and JOY_BTN33, BUT, in the drop down, select JOY_BTN31_OFF and JOY_BTN31_OFF. (they will show as grey IIRC) Understand?
When you have bound those, hop in the cold and dark and check.
Crossing my fingers now!