Different Colors for Different Programming Languages (Syntax Highlighting)?

Hi,

DocBook supports syntax highlighting in programlisting elements with
the help of the language attribute and the highlighting stylesheets
({fo,*html*}/highlight.xsl and highlighting/common.xsl). This works for
me.

Now I'm wondering if I can go it a bit further. Usually, customizing
the colors are done in xslthl mode. However, as it seems, I cannot get
the original language attribute anymore. I would like to implement
different colors for different programming languages. 

How can I do that? Is there a recommended procedure?

Thanks!

-- 
Gruß/Regards,
    Thomas Schraitle