php-class kaldes fra XML

Jeg har noget php, der parser xsl/xml. Problemet er data fra db'en skal hentes over i XML'en via et kald til en php-class (getPage) via dataSrc. Se kode nedenfor:

XML
<?xml version="1.0" ?>
<DOCUMENT>
<page dataSrc="getPage" PARAM0="form.id">
  <id/>
  <navn/>
</page>
</DOCUMENT>

XSL
<?xml version="1.0" encoding="ISO-8859-1" ?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output doctype-public="-//W3C//DTD HTML 4.0 Strict//EN" indent="yes" encoding="ISO-8859-1"/>
<xsl:template match="/">
<html>
<head>
<title>Edit</title>
</head>
<body>
  <xsl:apply-templates/>
</body>
</html>

<xsl:template match="DOCUMENT">
...bla. bla. bla.......
<xsl:value-of select="/DOCUMENT/page/navn"/></p>
...bla. bla. bla.......
</xsl:template>

</xsl:stylesheet>

PHP
<?php
$xh = xslt_create();

if (xslt_process($xh, 'editpage.xml', 'editpage.xsl', 'result.xml'))
{
  readfile('result.xml');
}
else
{
  echo "Sorry, could not transform. The reason is that " . xslt_error($xh) . ". The error code is " . xslt_errno($xh);
}
xslt_free($xh);

class getPage extends SQL
{
  function getPage ($params)
  {
        $sql = "SELECT * FROM design WHERE id = ".$params[0];       
            $this->sql(array($sql));     
  }
}
?>