ps.map - changing background color

I am trying to create a postscript file, using a region that is larger that
the raster map I want to plot. The raster map is a satellite image (created
using i.composite. I want to have a white background above (and around) the
image so I can have text above the image (not in the image). The ps I do
create with this image always has a black background, so I have to create
white text so it will show.

Is there something I can easily do in ps.map to have the background white?
The only other way I can think of is to set the region to the size I want,
then run r.resample, and use the resampled image in ps.map? Surely there
must be a better way.

Try setting category value 0 to white using d.colors.

Ronald Wiemer