Razer Naga Trinity - Middle Click Mapping

I’m switching over from another mouse and I’ve always bound my scroll wheel middle click in MMOs to my movement ability.  I’ve been trying to rebind the mouse-wheel mappings using Synapse, but they don’t seem to register on the mouse, but only the mouse wheel/DPI buttons - side panels bind fine.

I’m sure I’m missing something, but the forums mostly focus on left clicking issues or keypad issues. I didn’t see anything about remapping the scroll click function to a key press not working.   Anyone able to help me out?