Hi Peter,
I've just done this successfully on a Quando II!
Disconnecting the pedal sensor didn't work, it required some delicate work removing heatshrink, breaking into the wiring near the bottom bracket and some careful soldering to repair a wire which had been cut short on the pedelec model. Then I also had to make a connection up at the battery indicator to complete the job.
You need to be confident you can carry out the snipping, soldering, re-assembly and re-heat shrinking without damaging the rest of the wiring.
If you want to go ahead let me know and I'll give you more details of exactly what to do.
Hope this helps!