DOCBOOK-APPS: underline chars in tex using dsssl

[Doug du Boulay <ddb@R3401.msl.titech.ac.jp>]

I need to highlight default command options in the pdf/tex rendering of a 
document. 
Because commands are all already in bold teletype font and I would
prefer not to use color (for b&w printing) and italic bold teletype is not 
quite so obvious, I was hoping that there was some way to specify an 
underline font/type/face within dsssl.

Seems to be no mention of underline in the dsssl spec.
Does anyone have any info?
or is there someway to implement underlining within pdfjadetex.cfg ?

thanks 
Doug