This started from trying to get the backlight control working in Primo on my (wince) sat nav. I now don't think that is possible because I've got into control panel in wince and there is no backlight control there. I assume Primo will try to call a windows backlight control so I'm unlikely to get backlight to work in Primo if it doesn't work in windows.
My sat nav has a BacklightCTL.exe in \windows which ...