Thanks for your advices, I managed to get a standar 1.44Mb PC Floppy working with the Dragon.
For me, it appears as Drive 2, and i'd need it as Drive 1. I guess the twist in the cable is the same as you described, pins 10 and 12, right?
Edit: They were pins 10 and 12 indeed
I have now a working 3.5" drive as Drive 1, thanks for the tips!