XInclude problem

[kyru]

¿Why doesn't XInclude add the content of the file it refers to the master file? I have those two xml files:

master.xml

<?xml version="1.0" encoding="UTF-16"?>
<?xml-stylesheet href="master.xsl" type="text/xsl"?>
<a xmlns:xsi="

http://www.w3.org/2001/XMLSchema-instance"

xmlns:xi="

http://www.w3.org/2001/XInclude">

<xi:include href="a.xml"/>
Pruena
</a>

a.xml
<?xml version="1.0" encoding="UTF-16"?>
<algo2>
test
</algo2>


If I test master.xml with a web navigator it doesn't seem to include a.xml, in fact, the master.xsl file contains the following transformation:

<h1> <xsl:value-of select="algo2"/> </h1>

And seems to be completely ignored showing a blank page instead.