DOCBOOK-APPS: Setting shade.verbatim attribute value from commandline(xsltproc)

Hi,

In html/param.xsl, the bgcolor attribute for shade.verbatim is set to
"#E0E0E0".  I would like to use "#D8D8D8".  I cannot determine how to
set the bgcolor attribute from the command line using xsltproc.  Or must
I need to use a customization layer?

Thanks to Norm, Bob, and Daniel for all their fine work!