Getting Saxon XHTML to work

I'm trying to get Saxon to output XHTML. Following the instructions in
Bob's book I added the Saxon extensions to my customization layer:
<?xml version="1.0" encoding="UTF-8"?>

<xsl:stylesheet 
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:saxon="http://icl.com/saxon"
xmlns="http://www.w3.org/1999/xhtml"
version="1.0">

<xsl:import href="../lib/docbook-xsl/xhtml/chunk.xsl"/>

<xsl:import href="ziona_all.xsl"/>

<xsl:import href="ziona_html_all.xsl"/>

<xsl:import href="ziona_html_multipart.xsl"/>

<xsl:import href="ziona_html_break_on_section.xsl"/>

<xsl:import href="ziona_html_wholebook.xsl"/>

<xsl:import href="ziona_html_chunker.xsl"/>

<xsl:import href="fuse_html_user_head_content.xsl"/>

<xsl:import href="ziona_html_olinks_use.xsl"/>

<xsl:import href="ziona_html_callouts_use.xsl"/>

<xsl:import href="ziona_html_titlepage.xsl" /> 

<xsl:import href="ziona_html_override_abstract.xsl" /> 

<xsl:import href="fuse_footer_content.xsl"/>

<xsl:output method="saxon:xhtml" /> 

</xsl:stylesheet>

However, it does not seem to have any effect at all on the output. What
am I missing?

Thanks,
Eric J.