I also have an Infill G4 and am testing CF 1.46 before I commit to purchase. I have found that the radio problems you describe above are exactly the same for me. With the added problem of after selecting 'scan' and it stops at a station and you deselect the scan button, the frequency sometimes (not always) starts scanning backwards. It cycles through the Freq range continuously backwards. The only way to stop this is to re start CF again.
On the other topic of having multiple actions for the same buttons (i.e. whilst having the radio module open the hotkeys will only work for radio presets etc, and whilst in the Media module the same hotkeys will only select next track etc) this would be a much sought after ability and one I havenít had a chance to experiment with. Hopefully this function exists somewhere.
Also, can you describe how you got the steering wheel controls to work in the Infill G4? I have a Can Bus system which I donít think that compatible.