Hey mate this might be a bit late, but you need to use 'power strip' to get the custom resolution... I had this exact problem.
Just google power strip, i used the one from guru3d.
I've got a d201gly(which supports 800x480 natively), but I can't get it to display 800x480 correctly. 800x600 is just fine, but all it does for 480 is chop the top and bottom off so it looks like a widescreen movie. I've tried reinstalling drivers and messing with settings on the monitor, but so far no luck. Anyone experienced this same problem or know how to fix it?
Do you happen to have the settings you used? I've got powerstrip, but I haven't gotten anything to work so far.
If you have an nvidia gpu, use the Nvidia Control pannel to make the custom resolution... then open power strip in your system tray just right click on its icon and go to display profiles then use that slider in there to select your custom resolution.
Hope that helps, unless there is another part your having trouble with? let me know and i'll help out.
Na, no nvidia. It is onboard sis graphics. I know there was mention of the settings for powerstrip, but the "everything you need to know" thread is pretty mangled and searching came up with nothing. I assume I have the timings off...