matching namespace declaration

Hi everybody,

We have a bunch of documents with the following structure

<meta:htmldescription xmlns:meta="http://www.cetic.be/retroweb";>
        <meta:element>....</meta:element>
        ...
        <meta:element>...</meta:element>
</meta:htmldescription>

We want to transform these documents using xslt and would like to check at 
the same time that they have the correct namespace declaration.
We tried with the following template but it doesn't work

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"; 
version="1.0" xmlns:meta="http://www.cetic.be/retroweb";>
                  <xsl:output method="xml" indent="yes"/>
        <xsl:template match="meta:htmldescription[(_at_)xmlns:meta = 
'http://www.cetic.be/retroweb'">
                <root>
                        <xsl:apply-templates/>
                </root>
        </xsl:template>
...
</xsl:stylesheet>

can somebody help us

Thanks in advance