Zoom Setting Still Not Sticking In Live TV

I reported this problem on the beta and hoped that it would be fixed by now in the RC.

I have a widescreen Hitachi plasma with a native resolution of 1024x1024. My HTPC is connected via VGA using 1368x1024 resolution through an ATI Radeon 4670 card which gives really excellent picture quality for live TV (with a few tweaks!). MC displays correctly full screen but I need to set it to Zoom 3 for live TV to remove the black bars top and bottom and fill the screen correctly for 16:9 aspect ratio.

The problem is that this setting will not stick and randomly changes back to Zoom 1 when I change channels. Sometimes it works and sometimes not regardless of content. Sometimes I can just see the picture change zoom an instant before the channel changes.

This is definitely a windows problem and not related to the graphics driver. I have used the driver automatically installed by Windows 7 and updated to Catalyst 9.4 with exactly the same results. WMP remembers the zoom correctly for DVD playback.

I have an identical setup running under Vista MC and the zoom, once set, always remains the same (Zoom 3).

Is there a way of making this setting stick as it should remain the default for all my TV viewing and I could not live with having to change zoom every other time I change channels? Any help would be much appreciated as without a solution I would not be able to adopt Windows 7 which would be a great shame considering all its other improvements over Vista.