IT WORKS! Thanks!!!
I also noticed now that in the "paths" option for PinMAME you have to select Display: "Default" not specifically select DISPLAY1 or DISPLAY2... Otherwise it will only be a black screen.
I have the same issue as OP, can't get either DMD or B2S to work. Both works in VPX after launching the game. Coming back out to PinballX only shows black screens for both "areas"...