Need some help converting an XML with XSLT 1.0 - xslt

Question

Need some help regarding the XSLT transformation of a flat file schema. Is it possible to combine the direct children of the Record node into one containing Record node? Child 512 is required and has min and max occurrence of 1 and marks the beginning of a new Record node.
Input:
<ns0:Root xmlns="">
<Header>
<node01>AA</node01>
<node02>123</node02>
</Header>
<Record>
<512>
<node01>BB</node01>
<node02>123</node02>
</512>
</Record>
<Record>
<513>
<node01>CC</node01>
<node02>123</node02>
</513>
</Record>
<Record>
<512>
<node01>DD</node01>
<node02>123</node02>
</512>
</Record>
<Record>
<515>
<node01>JJ</node01>
<node02>123</node02>
</515>
</Record>
<Record>
<512>
<node01>EE</node01>
<node02>123</node02>
</512>
</Record>
<Record>
<513>
<node01>FF</node01>
<node02>123</node02>
</513>
</Record>
<Record>
<514>
<node01>GG</node01>
<node02>123</node02>
</514>
<514>
<node01>HH</node01>
<node02>123</node02>
</514>
</Record>
<Footer>
<node01>II</node01>
<node02>123</node02>
</Footer>
</ns0:Root>
Desired Output:
<ns0:Root xmlns="">
<Header>
<item01>AA</item01>
<item02>123</item02>
</Header>
<Record>
<512>
<item01>BB</item01>
<item02>123</item02>
</512>
<513>
<item01>CC</item01>
<item02>123</item02>
</513>
</Record>
<Record>
<512>
<item01>DD</item01>
<item02>123</item02>
</512>
<515>
<item01>JJ</item01>
<item02>123</item02>
</515>
</Record>
<Record>
<512>
<item01>EE</item01>
<item02>123</item02>
</512>
<513>
<item01>FF</item01>
<item02>123</item02>
</513>
<514>
<item01>GG</item01>
<item02>123</item02>
</514>
<514>
<item01>HH</item01>
<item02>123</item02>
</514>
</Record>
<Footer>
<item01>II</item01>
<item02>123</item02>
</Footer>
</ns0:Root>
Thank you and kind regards
Philipp
P.S.: XSLT 2.0 is not available.

Answer 1

That's not legal XML (element names can't start with numbers), but supposing you renamed all the invalid elements to start with "r", you can do the following:
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" indent="yes"/>
<xsl:strip-space elements="*" />
<xsl:template match="#* | node()">
<xsl:copy>
<xsl:apply-templates select="#* | node()"/>
</xsl:copy>
</xsl:template>
<xsl:template match="Record[r512]">
<xsl:copy>
<xsl:apply-templates select="." mode="iterate" />
</xsl:copy>
</xsl:template>
<xsl:template match="Record" />
<xsl:template match="Record" mode="iterate">
<xsl:apply-templates />
<xsl:apply-templates select="following-sibling::Record[1][not(r512)]"
mode="iterate"/>
</xsl:template>
</xsl:stylesheet>
When run on this input:
<ns0:Root xmlns="" xmlns:ns0="nsss">
<Header>
<node01>AA</node01>
<node02>123</node02>
</Header>
<Record>
<r512>
<node01>BB</node01>
<node02>123</node02>
</r512>
</Record>
<Record>
<r513>
<node01>CC</node01>
<node02>123</node02>
</r513>
</Record>
<Record>
<r512>
<node01>DD</node01>
<node02>123</node02>
</r512>
</Record>
<Record>
<r515>
<node01>JJ</node01>
<node02>123</node02>
</r515>
</Record>
<Record>
<r512>
<node01>EE</node01>
<node02>123</node02>
</r512>
</Record>
<Record>
<r513>
<node01>FF</node01>
<node02>123</node02>
</r513>
</Record>
<Record>
<r514>
<node01>GG</node01>
<node02>123</node02>
</r514>
<r514>
<node01>HH</node01>
<node02>123</node02>
</r514>
</Record>
<Footer>
<node01>II</node01>
<node02>123</node02>
</Footer>
</ns0:Root>
Produces:
<ns0:Root xmlns:ns0="nsss">
<Header>
<node01>AA</node01>
<node02>123</node02>
</Header>
<Record>
<r512>
<node01>BB</node01>
<node02>123</node02>
</r512>
<r513>
<node01>CC</node01>
<node02>123</node02>
</r513>
</Record>
<Record>
<r512>
<node01>DD</node01>
<node02>123</node02>
</r512>
<r515>
<node01>JJ</node01>
<node02>123</node02>
</r515>
</Record>
<Record>
<r512>
<node01>EE</node01>
<node02>123</node02>
</r512>
<r513>
<node01>FF</node01>
<node02>123</node02>
</r513>
<r514>
<node01>GG</node01>
<node02>123</node02>
</r514>
<r514>
<node01>HH</node01>
<node02>123</node02>
</r514>
</Record>
<Footer>
<node01>II</node01>
<node02>123</node02>
</Footer>
</ns0:Root>