Tacx Booster and Power Meter

I’m new to trainers and have bought a Tacx Booster to keep me sane through Covid home life. I didn’t want a smart trainer for virtual group rides etc but just want to roll the legs and use my Quarq Power Meter and Garmin Edge + Auto upload to Strava to record activities and power.

while using the trainer my Garmin shows the power I’m making (quarq) however when I save the Activity it’s all zero. I presume this is because I don’t use a cadence/speed sensor and just use my garmin’s GPS for speed when out on rides. Hence the Garmin thinks no activity took place as no speed or distance (movement) 

is there any way to tell my Garmin to just record an activity using elapsed time and power so I can just do some power rides, FTP tests etc.