Section Chunking Problems

["McKinstry, Scott A" <scott.a.mckinstry@lmco.com>]

I am trying to get the html stylesheets to produce a complete preface with no section chunks.
My preface looks like this.

<preface id="P001">
	<title>Front Matter</title>
	<section>
		<title>Forward</title>
		<para>some text</para>
	</section>
	<section>
		<title>Safety Summary</title>
		<para>some text</para>
	</section>
</preface>

I have <xsl:param name="chunk.first.sections" select='0'/>

I get two files as output

pr01.htm    contains Front Matter and Forward
pr01s02.htm contains Safety Summary

I thought I had disabled chunking at the section level but must have missed something.
I would like the preface to be one file not two.