Copy only the inner elements in a WSO2 SOAP envelope and add a new namespace

can you help?

I am trying to extract the core elements from a WSO2 SOAP envelope and forward it to another SOAP service.

Any help is appreciated, thanks for reading

the BEFORE shows the input message I receive,
the AFTER shows the progress I've made so far,
the DESIRED is the output I want and the FINAL OUTPUT will enclose the DESIRED in an element called request, the request element is static so it does not need to be in the XSLT transformation and can be excluded from the XSLT transform if it simplifies the solution.

BEFORE:

<por:ReadMostRecentPrices xmlns:por="http://PAS_1_1.ESB.OOO.com">
         <header>
            <sourceSystem>EDQC</sourceSystem>
            <userName>someguy</userName>
            <createdUtc>2020-10-10</createdUtc>
            <notes>dev test</notes>
            <serviceKey>password-not</serviceKey>
            <serverEnvironmentType>development</serverEnvironmentType>
         </header>
         <mostRecentPricesSet>
            <securityDurableKeys>
               <securityDurableKey>LZ0080300001</securityDurableKey>
               <securityDurableKey>LZ0080300002</securityDurableKey>
            </securityDurableKeys>
            <priceScheme>01</priceScheme>
            <date>2020-10-10</date>
         </mostRecentPricesSet>
      </por:ReadMostRecentPrices>

AFTER:

	<por:ReadMostRecentPrices xmlns:por="http://PAS_1_1.ESB.OOO.com">
			 <mostRecentPricesSet>
				<urn:securityDurableKeys xmlns:urn="urn:epaservice">
				   <securityDurableKey>LZ0080300001</securityDurableKey>
				   <securityDurableKey>LZ0080300002</securityDurableKey>
				</urn:securityDurableKeys>
				<urn:priceScheme xmlns:urn="urn:epaservice">01</urn:priceScheme>
				<urn:date xmlns:urn="urn:epaservice">2020-10-10</urn:date>
			 </mostRecentPricesSet>
		  </por:ReadMostRecentPrices>

DESIRED:

	<urn:securityDurableKeys xmlns:urn="urn:epaservice">
	  <urn:securityDurableKey>LZ0080300001</urn:securityDurableKey>
	  <urn:securityDurableKey>LZ0080300002</urn:securityDurableKey>
	</urn:securityDurableKeys>
	<urn:priceScheme xmlns:urn="urn:epaservice">01</urn:priceScheme>
	<urn:date xmlns:urn="urn:epaservice">2020-10-10</urn:date>

FINAL OUTPUT

<?xml version="1.0" encoding="UTF-8"?>
<urn:request xmlns:urn="urn:epaservice">
  <urn:securityDurableKeys>
    <urn:securityDurableKey>LZ0080300001</urn:securityDurableKey>
    <urn:securityDurableKey>LZ0080300002</urn:securityDurableKey>
  </urn:securityDurableKeys>
  <urn:priceScheme>01</urn:priceScheme>
  <urn:date>2020-10-10</urn:date>
</urn:request>

this my XSLT:

         <?xml version="1.0" encoding="UTF-8"?>
         <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:msxsl="urn:schemas-microsoft-com:xslt" version="1.0" exclude-result-prefixes="msxsl" xmlns:urn="urn:epaservice" xmlns:PortfolioAccountingService_1_1="http://PAS_1_1.ESB.OOO.com">
           <xsl:output method="xml" omit-xml-declaration="yes" indent="yes">
           </xsl:output>
           <xsl:template match="@* | node()">
             <xsl:copy>
               <xsl:apply-templates select="@* | node()">
               </xsl:apply-templates>
             </xsl:copy>
           </xsl:template>
           <!-- Removes the header START -->
           <xsl:template match="header">
           </xsl:template>
           <!-- Removes the header END -->
           <!-- mostRecentPrices operation START -->
           <xsl:template match="PortfolioAccountingService_1_1:ReadMostRecentPrices/mostRecentPricesSet/*">
             <xsl:element name="urn:{local-name()}" namespace="urn:epaservice">
               <xsl:apply-templates select="@* | node()"/>
             </xsl:element>
           </xsl:template>
           <xsl:template match="PortfolioAccountingService_1_1:ReadMostRecentPrices/mostRecentPricesSet/securityDurableKeys/*">
             <xsl:element name="urn:{local-name()}" namespace="urn:epaservice">
               <xsl:apply-templates select="@* | node()"/>
             </xsl:element>
           </xsl:template>
           <!-- mostRecentPrices operation END -->
         </xsl:stylesheet>

Constraints or gotchas:

• I am using Windows PowerShell and System.Xml.Xsl.XslCompiledTransform to test my transform which works perfectly if I use <xsl:template match="/"> in the first template match
• The production system uses org.apache.synapse.mediators.transform.XSLTMediator, and when I use the directive <xsl:template match="/"> the Apache XSLT processor fails with the error in bold below

• It seems like I have to use <xsl:template match="@* | node()">

TID: [0] [ESB] [2020-10-09 09:02:24,722] ERROR {org.apache.synapse.mediators.transform.XSLTMediator} - Unable to perform XSLT transformation using : Value {name ='null', keyValue ='PortfolioAccountingService_1_1_EPAOutbound_XSLT'} against source XPath : s11:Body/child::[position()=1] | s12:Body/child::[position()=1] reason : javax.xml.stream.XMLStreamException: ParseError at [row,col]:[8,14]
Message: The markup in the document following the root element must be well-formed. {org.apache.synapse.mediators.transform.XSLTMediator}
org.apache.axiom.om.OMException: javax.xml.stream.XMLStreamException: ParseError at [row,col]:[8,14]
Message: The markup in the document following the root element must be well-formed.

Here's a way you could do it:

<?xml version="1.0" encoding="UTF-8"?>
 <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    version="1.0"
    xmlns:urn="urn:epaservice" 
    xmlns:por="http://PAS_1_1.ESB.OOO.com"
    exclude-result-prefixes="por">
     
  <xsl:output method="xml" omit-xml-declaration="yes" indent="yes"/>

  <xsl:template match="/">
    <xsl:apply-templates select="por:ReadMostRecentPrices/mostRecentPricesSet"/>
  </xsl:template>
  
  <xsl:template match="mostRecentPricesSet">
    <xsl:apply-templates select="securityDurableKeys"/>
    <urn:priceScheme xmlns:urn="urn:epaservice"><xsl:value-of select="priceScheme"/></urn:priceScheme>
    <urn:date xmlns:urn="urn:epaservice"><xsl:value-of select="date"/></urn:date>
  </xsl:template>
  
  <xsl:template match="securityDurableKeys">
    <urn:securityDurableKeys xmlns:urn="urn:epaservice">
      <xsl:apply-templates select="securityDurableKey"/>
    </urn:securityDurableKeys>
  </xsl:template>
  
  <xsl:template match="securityDurableKey">
    <urn:securityDurableKey><xsl:value-of select="."/></urn:securityDurableKey>
  </xsl:template>
  
</xsl:stylesheet>

See it working here: https://xsltfiddle.liberty-development.net/3MEcZxB

It's much simpler if you can test your transformation on the same engine than the one you will be using on your server.