DOCBOOK: ProgramListing shading

I am a DocBook newbie.  My programlisting output for html is not shaded and I 
would like them to be shaded.  

I searched the web on "docbook shading" and found some references to 
%verbatim-shading%.  The Definitive Guide did not have this parameter.

I am using OpenJade 1.3
My document is :
<!DOCTYPE book PUBLIC "-//OASIS/DTD DocBook 4.1//EN">

Thanks,
-- 
mike