I have a Pioneer SC-LX82 amp and I've recently had the SKY HD HDMI 5.1 update - I've gone in to the settings on the amp to reassign the sound output from 'co-axial' to 'off' as the HDMI will now be relaying sound - it works fine but after switching off, the amp seems to revert to previous settings and reassigns to 'co-ax' for sound - what am I missing here??