@IanRoberts, @MichaelKay, with your help, i figured out how to create an escaped xml parser, and this working xslt is the result. Thanks for your help!
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"
xmlns:exsl="http://exslt.org/common"
extension-element-prefixes="exsl"
xmlns:xsi="http://www.w3.org/2001/XMLSchema">
<xsl:output indent="yes"/>
<xsl:template match="/">
<xsl:variable name="withoutCDataStart"
select="substring-after(root/row/field, '&lt;![CDATA[')"/>
<xsl:variable name="withoutCDataEnd"
select="substring-before($withoutCDataStart, ']]&gt;')"/>
<xsl:variable name="unEscapedXml">
<xsl:call-template name="unescape">
<xsl:with-param name="text" select="$withoutCDataEnd"/>
</xsl:call-template>
</xsl:variable>
<xsl:variable name="parsedXml_">
<xsl:call-template name="parseXml">
<xsl:with-param name="text" select="$unEscapedXml"/>
</xsl:call-template>
</xsl:variable>
<xsl:variable name="parsedXml" select="exsl:node-set($parsedXml_)"/>
<comprobante>
<idArchivo>
<xsl:attribute name="etiquetaCFD">
<xsl:value-of select="$parsedXml/comprobante/inicioCFD/etiquetaCFD"/>
</xsl:attribute>
<xsl:value-of select="$parsedXml/comprobante/inicioCFD/idArchivo"/>
</idArchivo>
</comprobante>
</xsl:template>
<xsl:template name="unescape">
<xsl:param name="text"/>
<xsl:choose>
<xsl:when test="contains($text, '&')">
<xsl:value-of select="substring-before($text, '&')"/>
<xsl:variable name="afterAmp" select="substring-after($text, '&')"/>
<xsl:choose>
<xsl:when test="starts-with($afterAmp, 'amp;')">&</xsl:when>
<xsl:when test="starts-with($afterAmp, 'lt;')"><</xsl:when>
<xsl:when test="starts-with($afterAmp, 'gt;')">></xsl:when>
<xsl:when test="starts-with($afterAmp, 'quot;')">"</xsl:when>
<xsl:when test="starts-with($afterAmp, 'apos;')">'</xsl:when>
</xsl:choose>
<xsl:call-template name="unescape">
<xsl:with-param name="text" select="substring-after($afterAmp, ';')"/>
</xsl:call-template>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="$text"/>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
<xsl:template name="parseXml">
<xsl:param name="text"/>
<xsl:choose>
<xsl:when test="contains($text, '>')">
<xsl:variable name="topLevelTag">
<xsl:call-template name="getTopLevelTag">
<xsl:with-param name="text" select="$text"/>
</xsl:call-template>
</xsl:variable>
<xsl:variable name="openingTag">
<xsl:value-of select="$topLevelTag"/>
</xsl:variable>
<xsl:variable name="tagName">
<xsl:call-template name="getTopLevelTagName">
<xsl:with-param name="text" select="$text"/>
</xsl:call-template>
</xsl:variable>
<xsl:variable name="closingTag">
<xsl:value-of select="concat('</',$tagName,'>')"/>
</xsl:variable>
<xsl:variable name="firstNode">
<xsl:if test="not(contains($topLevelTag,'/>'))">
<xsl:value-of select="substring-before(substring-after($text,$openingTag),$closingTag)"/>
</xsl:if>
</xsl:variable>
<xsl:variable name="afterFirstNode">
<xsl:choose>
<xsl:when test="not(contains($topLevelTag,'/>'))">
<xsl:value-of select="substring-after($text,concat($firstNode,$closingTag))"/>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="substring-after($text,$topLevelTag)"/>
</xsl:otherwise>
</xsl:choose>
</xsl:variable>
<xsl:element name="{$tagName}">
<xsl:call-template name="createAttributes">
<xsl:with-param name="text" select="$topLevelTag"/>
</xsl:call-template>
<xsl:call-template name="parseXml">
<xsl:with-param name="text" select="$firstNode"/>
</xsl:call-template>
</xsl:element>
<xsl:call-template name="parseXml">
<xsl:with-param name="text" select="$afterFirstNode"/>
</xsl:call-template>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="$text"/>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
<xsl:template name="getTopLevelTagName">
<xsl:param name="text"/>
<xsl:choose>
<xsl:when test="contains($text, '>')">
<xsl:variable name="tagWithAttributesWithoutEnd">
<xsl:value-of select="substring-before($text, '>')"/>
</xsl:variable>
<xsl:variable name="tagWithAttributesWithoutBegining">
<xsl:value-of select="substring-after($tagWithAttributesWithoutEnd, '<')"/>
</xsl:variable>
<xsl:variable name="tagName">
<xsl:choose>
<xsl:when test="contains($tagWithAttributesWithoutBegining,' ')">
<xsl:value-of
select="substring-before($tagWithAttributesWithoutBegining, ' ')"/>
</xsl:when>
<xsl:otherwise>
<xsl:value-of select="$tagWithAttributesWithoutBegining"/>
</xsl:otherwise>
</xsl:choose>
</xsl:variable>
<xsl:value-of select="$tagName"/>
</xsl:when>
</xsl:choose>
</xsl:template>
<xsl:template name="getTopLevelTag">
<xsl:param name="text"/>
<xsl:choose>
<xsl:when test="contains($text, '>')">
<xsl:variable name="tagWithAttributesWithoutEnd">
<xsl:value-of select="substring-before($text, '>')"/>
</xsl:variable>
<xsl:value-of select="concat($tagWithAttributesWithoutEnd,'>')"/>
</xsl:when>
</xsl:choose>
</xsl:template>
<xsl:template name="createAttributes">
<xsl:param name="text"/>
<xsl:choose>
<xsl:when test="contains($text, '="')">
<xsl:variable name="attributeName">
<xsl:value-of select="substring-before(substring-after($text,' '),'="')"/>
</xsl:variable>
<xsl:message>
<xsl:value-of select="$text"/>
</xsl:message>
<xsl:variable name="attributeValue">
<xsl:value-of select="substring-before(substring-after($text,concat($attributeName,'="')),'"')"/>
</xsl:variable>
<xsl:attribute name="{$attributeName}">
<xsl:value-of select="$attributeValue"/>
</xsl:attribute>
<xsl:call-template name="createAttributes">
<xsl:with-param name="text" select="substring-after($text,concat($attributeName,'="',$attributeValue,'"'))"/>
</xsl:call-template>
</xsl:when>
</xsl:choose>
</xsl:template>
</xsl:stylesheet>
It produces my required output:
<comprobante xmlns:xsi="http://www.w3.org/2001/XMLSchema">
<idArchivo etiquetaCFD="NCR">182NAI053402</idArchivo>
</comprobante>
I publish my work hoping could be helpfull to any other person.