annotating programlistings

[Stefan Seefeld <seefeld@sympatico.ca>]

I'm writing a tutorial for which I want to include various
programlistings. I'd like to annotate them, either by using
callouts, or just by providing line numbers and then referring
to those in my text.

However, I appear to be unable to use either of these,
as both seem to require special extensions only available
from xalan and saxon.

I have set

<xsl:param name="use.extensions" select="'1'"/>
<xsl:param name="use.callouts" select="'1'"/>
<xsl:param name="linenumbering.extension" select="'1'"/>

in my custom stylesheet, but I still get error messages
about unavailable extensions. I'm using xsltproc to generate
html, and I plan to use some fo processor (xep most likely)
for pdf generation.

Am I missing something ? I remember having successfully
used programlistingco in the past...

Thanks,
		Stefan