Please describe the problem:
xsl:key does not work as expected when using it in a variable declaration not in the scope of xsl:template.
Original Code is PHP5 but this does not seem to be an PHP issue.
Version Info (as stated by phpinfo())
libxslt Version: 1.1.23
libxslt compiled against libxml Version: 2.6.32
libexslt Version: 0.8.13

Should be easy to reproduce without PHP.

Steps to reproduce:
transform.php:
//normal xslt

$xsl = new DOMDocument;
$xsl->substituteEntities=true;
$xsl->load("details.xsl");

$xml = new DOMDocument;
$xml->substituteEntities=true;
$xml->load("data.xml");

$proc = new XSLTProcessor;
$proc->importStyleSheet($xsl);
$proc->transformToXML($xml);



data.xml:
<?xml version="1.0" encoding="ISO-8859-1"?>
<?xml-stylesheet type="text/xsl" ?>
<page>
    <formValues>
        <value name="detailModeChange">eval</value>
    </formValues>
</page>



transform.xsl:
<?xml version="1.0" encoding="ISO-8859-1"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
<xsl:output method="html" encoding="iso-8859-1"/>

<xsl:key name="formValuesName" match="/page/formValues/value" use="@name"/>

<xsl:variable name="changeMode1">
    <xsl:value-of select="/page/formValues/value[@name = 'detailModeChange']" />
</xsl:variable>

<xsl:variable name="changeMode2">
    <xsl:value-of select="key('formValuesName', 'detailModeChange')" />
</xsl:variable>

<xsl:template match="/">
    <xsl:message terminate="yes">
        <xsl:text>Key in Template: </xsl:text>
        <xsl:value-of select="key('formValuesName', 'detailModeChange')" />
        <xsl:text> -- raw XPATH in variable: </xsl:text>
        <xsl:value-of select="$changeMode1" />
        <xsl:text> -- key in variable: </xsl:text>
        <xsl:value-of select="$changeMode2" />
    </xsl:message>
</xsl:template>

</xsl:stylesheet>


Actual results:
Key in Template: eval -- raw XPATH in variable: eval -- key in variable: 

Expected results:
Key in Template: eval -- raw XPATH in variable: eval -- key in variable: eval

Does this happen every time?
yes

Other information: