Defining a variable for configuration file

Hi 

Could someone help me with this. I am defining the variable in a template
but looks like the $Config is not being recognized. 
I am getting error  'XSL transformation failed due to following error:
Invalid variable referenceErrror in XPath expression, invalid variable
reference" 

thanks
Harsha 



<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

	<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"
doctype-system="urn:/ShipmentOrderCreate.dtd"/>
	

	  <xsl:template match="/">
	  

		<xsl:if test="//storerkey = '1011'">

			<xsl:variable name="Config" select=
"document('1011CustomerConfig.xml')"/>

		</xsl:if>
	

			<xsl:element name="ShipmentOrderCreate">
								
				<xsl:element
name="CustomerCode"><xsl:value-of
select="$Config/ConfigurationFile/CustomerCode">
</xsl:value-of> </xsl:element>

			</xsl:element>

	</xsl:template>