> <xsl:when test="contains($string, '"')">

An XML attribute can't contain both double and single quotes.
I generally try to avoid the complexities of XML escaping by using

<xsl:variable name="quot">"</xsl:variable>
<xsl:when test="contains($string, $quot)">

Mike Kay


 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list