html/epub3 stylesheet bug

hi,
I'm using this type of processing instruction in my docbook 5 source:

 <?dbhtml-include href="">

and the docs say that the <html> wrapper inside the external doc will be removed, if I understand it correctly:

http://www.sagehill.net/docbookxsl/InsertExtHtml.html

However, here is a test file that does not remove the 'html' wrapper:

-------- db.xml ---------

<chapter xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="new" >

  <info><title>New</title></info>

  <para>

    <figure xml:id="output">

    <info><title>output</title></info>

    <?dbhtml-include href="">

  </para>

</chapter>

------ output.htm -------

<html>

  <div class="output">

    <div class="branch">

      <table>

        <tr><td>Output</td></tr>

      </table>

      <br/>

      <p>stuff</p>

    </div>

  </div>

</html>

The <html> tags are present inside the html file resulting from either of these commands:

xsltproc docbook/xsl-1.78.1/html/chunk.xsl db.xml

xsltproc docbook/xsl-1.78.1/epub3/chunk.xsl db.xml

Maybe I'm missing a parameter or this is a bug?

thanks,

--Tim