In that case you want to use a modified identity transform (see the xslt
spec or the faq for this list for more on this)

you just need three templates:

<xsl:template match="*">
 <xsl:copy>
 <xsl:copy-of select="@*"/>
 <xsl:apply-templates/>
 </xsl:copy>
</xsl:template>

<xsl:template match="TradeID">
 <TradeID><xsl:number/></TradeID>
</xsl:template>

<xsl:template match="ExtTradeID">
 <ExtTradeID><xsl:value-of select="../TradeID"/></ExtTradeID>
</xsl:template>

David


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