xsl insert calculated element - xslt-2.0

Question

I am relatively new to XSLT and am having major problems with something that should be relatively simple. I've searched the Internet for 2 days but can't get over the last hurdle of this problem.
Here is a simple version of the XML I want to transform:
<Payment xmlns="http://www.xxxxxx.com/CIB/GIFTS/PaymentFileSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xxxxxx.com/CIB/GIFTS/PaymentFileSchema.xsd ">
<Transaction>
<POSellerName>DAF KNITWEARS LTD. (PG)</POSellerName>
<PayeeName>883456789</PayeeName>
<CurrencyCode>USD</CurrencyCode>
<WTLCNumber>O0910122</WTLCNumber>
<VendorAppNumber>6031</VendorAppNumber>
<DocumentNumber>BEAI12000094</DocumentNumber>
<PODetail>
<PONumber>0887537</PONumber>
<QuantityShipped>2550</QuantityShipped>
<UnitOfMeasure>PCS</UnitOfMeasure>
<CurrencyCode>USD</CurrencyCode>
<AmountBilled>13226.37</AmountBilled>
</PODetail>
<PODetail>
<PONumber>0887567</PONumber>
<QuantityShipped>150</QuantityShipped>
<UnitOfMeasure>PCS</UnitOfMeasure>
<CurrencyCode>USD</CurrencyCode>
<AmountBilled>873</AmountBilled>
</PODetail>
<ChargeBackDetail>
<PONumber>0887567</PONumber>
<CurrencyCode>USD</CurrencyCode>
<ChargeBackAllocationAmount>-105</ChargeBackAllocationAmount>
<ChargeBackReferenceNumber>CB0872364C</ChargeBackReferenceNumber>
<UPC/>
</ChargeBackDetail>
<ChargeBackDetail>
<PONumber>0872355</PONumber>
<CurrencyCode>USD</CurrencyCode>
<ChargeBackAllocationAmount>-105</ChargeBackAllocationAmount>
<ChargeBackReferenceNumber>CB0872355A</ChargeBackReferenceNumber>
<UPC/>
</ChargeBackDetail>
</Transaction>
</Payment>
I want to insert an element at the end of each <PODetail> named
<AmountPaid>.
So I process each <PODetail> and look for a <ChargeBackDetail> with the same value in their respective elements. If found, the element would have the value of /PODetail/Amountbilled - /ChargeBackDetail/ChargeBackAllocationAmount, otherwise the value would be equal to /PODetail/Amountbilled. Below is he desired result for the PONumber elements.
<PODetail>
<PONumber>0887537</PONumber>
<QuantityShipped>2550</QuantityShipped>
<UnitOfMeasure>PCS</UnitOfMeasure>
<CurrencyCode>USD</CurrencyCode>
<AmountBilled>13226.37</AmountBilled>
<AmountPaid>13226.37</AmountPaid>
</PODetail>
<PODetail>
<PONumber>0887567</PONumber>
<QuantityShipped>150</QuantityShipped>
<UnitOfMeasure>PCS</UnitOfMeasure>
<CurrencyCode>USD</CurrencyCode>
<AmountBilled>873</AmountBilled>
<AmountPaid>768</AmountPaid>
</PODetail>
This is my XSLT:
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:pf="http://www.WellsFargo.com/CIB/GIFTS/TradeERP/PaymentFileSchema">
<xsl:template match="node()|#*">
<xsl:copy>
<xsl:apply-templates select="node()|#*"/>
</xsl:copy>
</xsl:template>
<xsl:template match="pf:PODetail">
<xsl:copy>
<xsl:apply-templates select="#* | node()"/>
<xsl:variable name="poNumber" select="pf:PONumber"/>
<xsl:variable name="poAmountBilled" select="number(pf:AmountBilled)"/>
<xsl:for-each select="//pf:Transaction/pf:ChargeBackDetail">
<xsl:variable name="poNumber" select="pf:PODetail/pf:PONumber"/>
<xsl:variable name="cbPONumber" select="./pf:ChargeBackDetail/pf:PONumber"/>
<xsl:variable name="cbAmount" select="number(./pf:ChargeBackDetail/pf:ChargeBackAllocationAmount)"/>
<xsl:if test='$poNumber = $cbPONumber'>
<AmountPaid><xsl:number value="$poAmountBilled - $cbAmount"/></AmountPaid>
</xsl:if>
</xsl:for-each>
<xsl:if test ="not(pf:AmountPaid)">
<AmountPaid><xsl:number value="$poAmountBilled"/> </AmountPaid>
</xsl:if>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
Any help would be greatly appreciated!
Gene

Answer 1

This transformation:
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:x="http://www.xxxxxx.com/CIB/GIFTS/PaymentFileSchema" exclude-result-prefixes="x">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:template match="node()|#*">
<xsl:copy>
<xsl:apply-templates select="node()|#*"/>
</xsl:copy>
</xsl:template>
<xsl:template match="x:PODetail">
<xsl:copy>
<xsl:apply-templates select="#*|node()"/>
<xsl:element name="AmountPaid"
namespace="http://www.xxxxxx.com/CIB/GIFTS/PaymentFileSchema">
<xsl:sequence select=
"sum((x:AmountBilled,
../x:ChargeBackDetail[x:PONumber eq current()/x:PONumber]
/x:ChargeBackAllocationAmount))"/>
</xsl:element>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
when applied on the provided XML document:
<Payment xmlns="http://www.xxxxxx.com/CIB/GIFTS/PaymentFileSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xxxxxx.com/CIB/GIFTS/PaymentFileSchema.xsd ">
<Transaction>
<POSellerName>DAF KNITWEARS LTD. (PG)</POSellerName>
<PayeeName>883456789</PayeeName>
<CurrencyCode>USD</CurrencyCode>
<WTLCNumber>O0910122</WTLCNumber>
<VendorAppNumber>6031</VendorAppNumber>
<DocumentNumber>BEAI12000094</DocumentNumber>
<PODetail>
<PONumber>0887537</PONumber>
<QuantityShipped>2550</QuantityShipped>
<UnitOfMeasure>PCS</UnitOfMeasure>
<CurrencyCode>USD</CurrencyCode>
<AmountBilled>13226.37</AmountBilled>
</PODetail>
<PODetail>
<PONumber>0887567</PONumber>
<QuantityShipped>150</QuantityShipped>
<UnitOfMeasure>PCS</UnitOfMeasure>
<CurrencyCode>USD</CurrencyCode>
<AmountBilled>873</AmountBilled>
</PODetail>
<ChargeBackDetail>
<PONumber>0887567</PONumber>
<CurrencyCode>USD</CurrencyCode>
<ChargeBackAllocationAmount>-105</ChargeBackAllocationAmount>
<ChargeBackReferenceNumber>CB0872364C</ChargeBackReferenceNumber>
<UPC/>
</ChargeBackDetail>
<ChargeBackDetail>
<PONumber>0872355</PONumber>
<CurrencyCode>USD</CurrencyCode>
<ChargeBackAllocationAmount>-105</ChargeBackAllocationAmount>
<ChargeBackReferenceNumber>CB0872355A</ChargeBackReferenceNumber>
<UPC/>
</ChargeBackDetail>
</Transaction>
</Payment>
produces the wanted, correct result:
<Payment xmlns="http://www.xxxxxx.com/CIB/GIFTS/PaymentFileSchema"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.xxxxxx.com/CIB/GIFTS/PaymentFileSchema.xsd ">
<Transaction>
<POSellerName>DAF KNITWEARS LTD. (PG)</POSellerName>
<PayeeName>883456789</PayeeName>
<CurrencyCode>USD</CurrencyCode>
<WTLCNumber>O0910122</WTLCNumber>
<VendorAppNumber>6031</VendorAppNumber>
<DocumentNumber>BEAI12000094</DocumentNumber>
<PODetail>
<PONumber>0887537</PONumber>
<QuantityShipped>2550</QuantityShipped>
<UnitOfMeasure>PCS</UnitOfMeasure>
<CurrencyCode>USD</CurrencyCode>
<AmountBilled>13226.37</AmountBilled>
<AmountPaid>13226.37</AmountPaid>
</PODetail>
<PODetail>
<PONumber>0887567</PONumber>
<QuantityShipped>150</QuantityShipped>
<UnitOfMeasure>PCS</UnitOfMeasure>
<CurrencyCode>USD</CurrencyCode>
<AmountBilled>873</AmountBilled>
<AmountPaid>768</AmountPaid>
</PODetail>
<ChargeBackDetail>
<PONumber>0887567</PONumber>
<CurrencyCode>USD</CurrencyCode>
<ChargeBackAllocationAmount>-105</ChargeBackAllocationAmount>
<ChargeBackReferenceNumber>CB0872364C</ChargeBackReferenceNumber>
<UPC/>
</ChargeBackDetail>
<ChargeBackDetail>
<PONumber>0872355</PONumber>
<CurrencyCode>USD</CurrencyCode>
<ChargeBackAllocationAmount>-105</ChargeBackAllocationAmount>
<ChargeBackReferenceNumber>CB0872355A</ChargeBackReferenceNumber>
<UPC/>
</ChargeBackDetail>
</Transaction>
</Payment>