, RS Mapper was intended for any sim - (take DCS, Il Sturmovik, or civ sims) - and they do not support those functions even trough key files 🙂
DCS supports key release. DCS GUI does not. It’s more painfull than editing BMS key file manually and also does not support one dx button to command 2 or more callbacks like BMS does, but they do.
Well, the GUI doesnt. BMS follows pretty standard DI convention there in that it supports only one POV hat, and up to 32 DI buttons (counting the POV buttons, so for a stick which has POV on it, then up to 28 buttons).
BMS supports up to 4 POV if it is on the primary(roll/pitch assigned) joystick. But never support any POV switches if its on non primary device. Primary device with 1 pov hat can assign 32DX + 8 Direction of 1 POV.