can't compile doc with colophon

[vincent <vvaquin@club-internet.fr>]

Hello, I'm new here.:-)
I'm beginning to have an intensive use of docbook. It's work fine but I 
have a difficulty with colophon and I have seen nothing that would help 
me, even here...
So I try to explain my difficulty.

<?xml version="1.0" encoding="UTF-8"?>
<article version="5.0" xml:lang="fr" xmlns="http://docbook.org/ns/docbook";>
<info><title>Test</title></info>

<section xml:id="introduction"><title>Introduction</title>
<para>Blah blahblah</para>
</section>

<colophon>
<para>colophon text</para>
</colophon>

</article>

The doc is valid and xsltproc create the .fo but fop complain :
page-sequence is not a valid child of fo:flow

The same document with "book" and "chapter" instead of "article " and 
"section" is ok (1)

I use xls-ns-stylesheet  1.75.2,  fop 1.0 and xsltproc on windows
I tried to use :
<xsl:param name="fop1.extensions" select="1"></xsl:param>
but no difference.
-----------------------------------------------------------------------------------------------
(1)  the same document with book work only if there is something before 
colophon :

<?xml version="1.0" encoding="UTF-8"?>
<book version="5.0" xml:lang="fr" xmlns="http://docbook.org/ns/docbook";>
<info><title>Test</title></info>

<chapter xml:id="introduction"><title>Introduction</title>
<para>Blah blahblah</para>
</chapter>

<colophon>
<para>colophon text</para>
</colophon>

</book>

above it's OK but this one :
<?xml version="1.0" encoding="UTF-8"?>
<book version="5.0" xml:lang="fr" xmlns="http://docbook.org/ns/docbook";>
<info><title>Test</title></info>

<colophon>
<para>colophon text</para>
</colophon>

</book>
which is valid don't work.