In Tux Guitar
How do you make it so that you can add tremolo picking to a bend?
It doesn't allow me to have both. 

Any solutions? 
You have to put in every individual note that you would play if you were tremolo picking, make them 16ths, 16th triplets, 32nds, whatever fits for the tempo. And then have them all as full pre-bends for example. Or if you're bending a note up whilst tremolo picking you might have to do one note not bent, one 1/4 tone, one 1/2 tone, one 3/4 tone, then full, etc.