Use Xpath Inside XSLT test clause
===

I am trying to put xpath expression as a variable inside a xslt test clause, as follows:

    <xsl:choose>
    <xsl:when test="../v:node[@InputName='{v:HeaderValue}']">
    </xsl:when>
    <xsl:otherwise>
    </xsl:otherwise>
    </xsl:choose>

However, it doesn't work, and always evaluates to false. Anyone knows why?