namespaced attribute handling in MSXML XSLT

Does anyone know of an error in MSXML's handling of namespaced
attributes? I have a template:

<xsl:template match="@*">
  <xsl:if test="not(namespace-uri()='http://example.com')">
    <xsl:copy-of select="."/>
  </xsl:if>
</xsl:template>

When I execute this in XML Spy, all the attributes other than those in
the namespace shown are copied to the result tree. When I try the same
thing using MSXML, all attributes are copied.

Any ideas?

Regards

Paul Spencer