transfer namespace within XSL

[Ivo Ottiger <ivo.ottiger@bluewin.ch>]

I try to transform the following XML Doc

<?xml version = "1.0" encoding = "UTF-8"?>
<PortfolioResp xmlns = "http://www.portfolio.org/Portfolio/Response"
xmlns:xhtml="http://www.w3.org/1999/xhtml">
	<Quote>
		<Symbol>SUNW</Symbol>
		<Time>9:51AM</Time>
		<Price>16.06</Price>
		<Change>-1.53%</Change>
		<Volume>3,729,800</Volume>
	</Quote>
</PortfolioResp>

whith the following XSL into a new one without namespace

<?xml version="1.0"?>
<!-- quotes.xsl: Transform to Quote.dtd vocabulary -->
<xsl:stylesheet version="1.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  xmlns:xhtml="http://www.w3.org/1999/xhtml">
  <xsl:output method="xml" doctype-system="Quote.dtd" indent="yes"/>
  <xsl:template match="/">
    <Quotes>
      <xsl:for-each select="xhtml:PortfolioResp/xhtml:Quote">
        <Quote>
          <Symbol Ticker="{xhtml:Symbol}"></Symbol>
          <Time><xsl:value-of select="xhtml:Time"/></Time>
          <Price><xsl:value-of select="xhtml:Price"/></Price>
        </Quote>
      </xsl:for-each>
    </Quotes>
  </xsl:template>
</xsl:stylesheet>

which should look like this one

<?xml version = "1.0" encoding = "UTF-8"?>
<Quotes>
	<Quote Symbol="SUNW">
		<Time>9:51AM</Time>
		<Price>16.06</Price>
	</Quote>
</Quotes>

But without any success. Can somebody help me.
Thanks.