how to convert to XSL 1.0

Hello All,

This is XSLT 2.0 source that splits and inbound message into multiple outputs... based on 'esp-po-data' node

I need help converting this into XSL 1.0 version to use in PI 7.1 EHP3

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="2.0">
<xsl:output method="xml" indent="yes" name="xml"/>
<xsl:template match="/">
             <xsl:for-each select="/esp/esp-po-data">		
             <xsl:variable name="filename"  select="concat('output_',  position(),'.xml')" />
             <xsl:value-of select="$filename" />
            <xsl:result-document href="{$filename}" format="xml" >
                  <xml>
	<esp>
	        <esp-po-data>
	              <xsl:copy-of select="po-header"/>
	        </esp-po-data>
	</esp>
	</xml>
              </xsl:result-document>
              </xsl:for-each>
</xsl:template>
</xsl:stylesheet>