Hi Pete,
Thanks for your very detailed answer.
The joystick is disabled in FS, so axis assignment in FS shouldn't have any effect, should they?
I am afraid this is not the reason. Joystick is disabled and calibration is ok (sensitivity max, null zone min).
That is likely to be the case, indeed. I tried with the following aircrafts: Aussim Warrior, PMDG 737, PMDG 747. The first two won't work with "send to FS". The 747 works with any method. (I asked PMDG why their 737 could behave differently than the 747 but they don't answer)
I did read that part of the manual. However because I don't know about the internals of FS nor about how panels integrate with FS and FSUIPC, I can't cleary understand what is the effect of "send direct FSUIPC" vs. "send to FS".
Anyway I think I can now better guess what could be happening: with "send direct to FSUIPC", aircraft panels cannot access the axis before FSUIPC calibration, which is where the flaps detents are created. So with "send to FS", some aircraft panels may intercept the axis before FSUIPC gets a chance to create the flap detents. Would that be correct?
Cheers,
Christophe.