alla fine sono riuscito a trovare un metodo.....
cioè ho costruito una funzione di tipo replace string......
ecco il codice
codice:
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:fo="http://www.w3.org/1999/XSL/Format">
<xsl:template name="replace-string">
<xsl:param name="text"/>
<xsl:param name="replace"/>
<xsl:param name="with"/>
<xsl:choose>
<xsl:when test="contains($text,$replace)">
<xsl:value-of select="substring-before($text,$replace)"/>
<xsl:value-of select="$with"/>
<xsl:call-template name="replace-string">
<xsl:with-param name="text" select="substring-after($text,$replace)"/>
<xsl:with-param name="replace" select="$replace"/>
<xsl:with-param name="with" select="$with"/>
</xsl:call-template>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="$text"/>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
</xsl:stylesheet>