There's one T2875.51 Campagnolo freehub body available in the States on
eBay here, but it's $80 + shipping & duties.
You could chuck a Shimano 10-speed cassette on there - without road grime and outdoor wear the shifting should be ok for 11 weeks until you can fit a Campagnolo cassette

(thougb it'll probably rattle like a bag of spanners at the extremes of the cassette!)
You could always Bluetooth your phone to the Neo (leaving the Ant+ for Zwift or your app of choice), stick it in 'slope' mode in the Tacx app and control the resistance via the phone, meaning you would barely need to shift gears at all. Shane Miller has a good video on this
here.