Hi crashdummy.
I have eventually been able to test the feather with my SAITEK Pro-Quadrant with XPlane 10 under windows 7.
Things have changed since the last time I used XPlane 9 with my SAITEK Pro-Quadrant.
I reinstalled my simulator in that order:
1/ I did the XPlane 10 installation.
2/ I downloaded three drivers from the ex-SAITEK (new Logitech) site for the rudder pedals, the yoke and the quadrant.
3/ Then I plugged my hardwares in the USB ports.
And everything seems to work well.
And even I am still not able to find a parameter to choose the feather position of a propeller, with my SAITEK Pro-Quadrant, I am now able to put a propeller in the feather position when I apply my propeller lever in the reverse position.
I made a test on the default Beechcraft 58 on the ground where it is possible to see the propeller in the feathered position.
Thanks for your help anyway. Wishing you a Happy New Year!