[docbook-apps] Courseware material authoring customization layer (Was: Recusive<section/>'s and their conclusions)

["Dimitry V. Ketov" <Dimitry dot Ketov at avalon dot ru>]

The matter of my question is that i'm working on customization layer for courseware 
material authoring.

Now I use following style for the (self assesment) labs markup:

<article role="labkit" lang="ru"
	 xmlns="http://docbook.org/docbook-ng";>
  <info>
    <title>Course Name</title>
    <authorgroup>
	...
    </authorgroup>
  </info>

  <section role="lab" >
    <title>Lab title</title>

    <highlights role="tasks">
	<!-- Lab tasks explanation -->
    </highlights>

    <highlights role="objectives">
	<!-- Lab objectives explanation -->
    </highlights>

    <section role="topic">
      <title>Topic title</title>

       <section role="topic">
         <title>Subtopic title</title>

         <!-- Topic matter -->
       </section>

       <section role="exercise">
         <title>Exercise title</title>

         <!-- Exercise matter -->
       </section>
    </section>

<!-- Here I want to conclude lab: quiz, etc... -->

  </section>
</section>

but due to current DTD and DocBook NG schema it's not possible to use something "more 
semantic" (e.g <highlights/>) than section to conclude.

Any thoughts?