> (ah, I see that David beat me to it with a much shorter approach ;)

Nah, that was the long approach, the shorter approach is just to use a
single xpath 2 expression:



<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  
 <xsl:output method="text"/>

 <xsl:template match="shipment">
   <xsl:value-of select="'&#10;REC1*',header/string(shipmentId),
			 detail/po/(if(position() mod 2 = 1) then '&#10;REC2*' else '*', string()),
			 detail/containers/box/(if(position() mod 4 = 1) then '&#10;REC3*' else '*',string())"
		 separator=""/>
 </xsl:template>
</xsl:stylesheet>

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