USB DivX playback with annoying gray background

[qanda]This question is published in the hardware section for the Panasonic DMR-EZ485V DVD Recorder. Click here to view full specs.[/qanda]I was really looking forward to playing DivX movies off of a USB drive. However, whenever I play a widescreen video off the USB drive, the normal “black bars” above and below the video are replaced with an ugly bright gray color. It is very distracting and makes movies almost unwatchable. Does anyone know how to change the gray color to black?

There’s probably something in the manual about this:

http://tv.manualsonline.com/manuals/mfg/panasonic/dmrez485v_dmrez48v.html