Can't get vive tracker working as a virtual camera

Hey folks. running into a wall trying to get vive tracker to work within unreal as a virtual camera. created blueprint, set the role, and the kink is when i try to assign the binding to the camera tracker in steamvr, i never get the option for “Special_1”. Scoured the net for things to try but not making any progress. Going to try Richard Frantzén’s method tomorrow, but hope someone around here may have some suggestions.