If you don't have a real DMD then you want to use the --virtual-stay-on-top parameter not the --no-virtual option like Mike says, also i don't think you should place dmdevice in the PinballX folder either when using a virtual DMD (i use virtual DMD on a 3rd screen and i haven't)
I don't use FX3, but i assume the pac key is the same as the vni.key (see first post https://vpuniverse.com/forums/topic/9051-new-release-v220-final/), and what i think is the discussion Mike mentioned is in the beta testing thread posts around here, https://vpuniverse.com/forums/topic/8845-new-release-v220-beta2/?do=findComment&comment=74143