namespace-uri() method returns emty,using xalan 2.0

Hey list:
i tried with all of the following options to get the namespace-uri(),all of my efforts are in vain.In all of these cases it returns empty.Help needed....
xml:
<?xml version="1.0"?>
 <a:root xmlns:a="name-a">
 	<b:sub xmlns:b="name-b"/>
 	<c:sub xmlns:c="name-c"/>
 </a:root>
xsl:method1:
<?xml version="1.0"?>
 <xsl:stylesheet
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform" 
 version="1.0"
   xmlns:a="name-a"  xmlns:b="name-b"  
 xmlns:c="name-c">
 <xsl:template match="/">
   <xsl:for-each select="a:root">
    <uri><xsl:value-of select="namespace-uri()"/></uri>
  </xsl:for-each>
 </xsl:template>
 </xsl:stylesheet>

xsl: method:2
<?xml version="1.0"?>
 <xsl:stylesheet
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform" 
 version="1.0"
   xmlns:a="name-a"  xmlns:b="name-b"  
 xmlns:c="name-c">
 <xsl:template match="/">
   <xsl:for-each select="*/[name()='a:root']">
    <uri><xsl:value-of select="namespace-uri()"/></uri>
  </xsl:for-each>
 </xsl:template>
 </xsl:stylesheet>

challa



 


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