Hi, I solve the problem in this way...
<xsl:element name="query"><xsl:attribute name="id">OrderDateFrom</xsl:attribute><xsl:attribute name="value"> <xsl:value-of select="$MyOrderDateFrom"/></xsl:attribute></xsl:element><xsl:element name="query"><xsl:attribute name="id">OrderDateTo</xsl:attribute><xsl:attribute name="value"> <xsl:value-of select="$MyOrderDateTo"/></xsl:attribute></xsl:element>
Let me know if some one have another solution.
Thanks!