Missing prop feathering sound

I fly Aeroworx' excellent King Air B200. My controllers are a CH Products Yoke and Pedals and a single Saitek Pro Flight Throttle Quadrant. All axes and buttons are set up and controlled through FSUIPC. I am finding that I am not getting any change in sound as I move the prop lever, and in particular when the props are feathered. I originally used the default Aeroworx sound package, and I don't recall whether I could hear a sound change when feathering - but I stopped using these sounds as the engine sounds were linked to RPM instead of torque. I then started using a freeware sound package by a chap called Leon Medado, as these were linked to torque. I was certainly not getting any feathering sounds with this package. I have now purchased and installed Turbine Sound Studios King Air package, and these sound great. The demo video from TSS actually demonstrates the change in sound when feathering the props (admittedly on the default King Air 350). But I'm still not getting any feathering sounds. I have posted on the Aeroworx King Air forum, and other users have confirmed that they are getting feathering sounds. It would therefore seem that the problem is not with sound package, but with something else.Does anybody have any ideas about how to fix this?Thanks for your help.Adrian