The VM70 and VM92 monitors have widescreen (16:9 ratio) dimensions. Both feature native WVGA 800x480 resolutions.
Unfortunately, most videocards use a graphic chipset that doesn't support 800x480.
You can use a program called Powerstrip available from http://www.entechtaiwan.com. Please visit the website to download the free trial version and to check for compatibility with your videocard.

For Linux users, you can use the following Modeline in your XF86Config file to get 800x480:
Modeline "800x480" 31.746 800 864 944 1000 480 508 511 525 -hsync -vsync
or
Modeline "800x480" 31.746 800 860 940 1000 480 508 511 525 -hsync -vsync
or
Modeline "800x480" 38.55 800 832 976 1032 480 489 495 613 -hsync -vsync