cmdsynopsis omits xml:id

hi, when I convert DocBook 5 using the 1.77 html (chunk) stylesheets, the cmdsynopsis element is rendered as a div, but the xml:id is omitted. Is this a bug or am I misunderstanding? I would have expected the xml:id to come through as an id in the html.

Test document:

<chapter xmlns="http://docbook.org/ns/docbook"

         version="5.0" xml:id="abc">

  <info><title>The Chapter</title></info>

  <section xml:id="abd">

    <info><title>The Section</title></info>

    <para>

      <cmdsynopsis xml:id="abe" sepchar=" ">

        <command>The Command</command>

        <arg choice="plain">variable-list</arg>

        <arg choice="plain">;</arg>

      </cmdsynopsis>

    </para>

  </section>

</chapter>

with this command line:

xsltproc /path/to/docbook/xsl-1.77.1/html/chunk.xsl test.xml

the cmdsynopsis element results in this block of html (I expected the id "abe" on the div):

 <div class="cmdsynopsis">

   <p>

     <code class="command">The Command</code>

     variable-list   ;

   </p>

 </div>

thanks,

--Tim