Assemblies in DocBook 5.1: generating multiple structure outputs using assemble.xml

[graeme@heliocentrik.net]

Hi there,
My use case is that I want to maintain a single assembly file
per-project, containing all the <structure> elements which define my
document output. The problem I'm having is that XSLTproc (and the other
XSLT processors I've tried) only seem to generate assembled DocBook
files for the first <structure> element encountered, and the rest are
ignored.

My assembly file looks like:

<structure xml:id="article1">
	<output renderas="article" />
	<module resourceref="thing1"/>
    <module resourceref="thing2"/>
</structure>

<structure xml:id="book1">
    <output renderas="book" />
    <module resourceref="thing3"/>
    <module resourceref="thing4"/>    
</structure>

<structure xml:id="book2">
    <output renderas="book" />
    <module resourceref="thing3"/>
    <module resourceref="thing4"/>    
</structure>

When I run assemble.xml (version v 1.10 2012-04-10 07:56:58 from the
latest stylesheets), I'm invoking it like this:

xsltproc ~/docbook-xsl/assembly/assemble.xsl assembly-file.xml

In the output, I get the <article> element for 'article1', but 'book1'
and 'book2' are ignored.

Here are the details of the xsltproc tool I'm using:

Using libxml 20703, libxslt 10124 and libexslt 813
xsltproc was compiled against libxml 20703, libxslt 10124 and libexslt
813
libxslt 10124 was compiled against libxml 20703
libexslt 813 was compiled against libxml 20703

Thanks in advance for any guidance.

Graeme