Is this right for When 4 < 5 and 1 < 2 ?
<xsl:when test="4 < 5 AND 1 < 2" >
<!-- do something -->
</xsl:when>
Not quite, the AND has to be lower-case.
<xsl:when test="4 < 5 and 1 < 2">
<!-- do something -->
</xsl:when>