Tacx Sirius - any ideas for power curve?

I’ve just joined Zwift using a Tacx Sirius with my Garmin speed and cadence sensors. It’s not supported but I was wondering if I should pretend it’s another supported model because I’m sure the estimated power ratings are far too low for the effort I’m making. Did a group ride with my club mates and was giving dropped by guys I’d easily drop on the road.

I have a similar problem. I am using the Minoura V270 dumb trainer but I have a copy of the Minoura’s power curves. Using my Garmin to measure wheel speed I pedalled at 45km/h and Zwift reckoned I was putting out a massive (for me) 300W! The V270 power curve says 166W at this wheel speed which is much more realistic. It would be good if we could find the power curve data that Zwift uses for comparison.