Please try this XSL..

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" 
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
   <xsl:output method="xml" indent="yes"/>
	
  <xsl:template match="node() | @*">
     <xsl:copy>
         <xsl:apply-templates select="node() | @*" />        
     </xsl:copy>	
  </xsl:template>
	
  <xsl:template match="car">
     <car>
          <xsl:attribute 
name="car_ref">http://someurl/standard</xsl:attribute>   
          <xsl:apply-templates />
    </car>
</xsl:template>
	
</xsl:stylesheet>

Regards,
Mukul


"Torsten Reichert" wrote:

> Hi experts
> 
> I wonder, what the xsl looks like to achieve the following transformation:
> 
> ==== INPUT =====
> <?xml version="1.0"?>
> <source car_ref_default="http://someurl/standard">
>    <car>BMW</car>
> </source>
> 
> ==== OUTPUT to be achieved =====
> <?xml version="1.0"?>
> <source car_ref_default="http://someurl/standard">
>    <car car_ref=""http://someurl/standard">BMW</car>
> </source>
> 
> Does anyone see how this is done ?
> 
> Thank you
>