I'm not sure if I understand your question correctly: would setting output to "text" help?
<xsl:output method="text" encoding="utf-8" indent="no"/>
Example XSLT sheet:
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="text" encoding="utf-8" indent="no"/>
<xsl:template match="/">
<xsl:apply-templates />
</xsl:template>
<xsl:template match="a">
<a b='<xsl:value-of select="@b"/>'>
</xsl:template>
</xsl:stylesheet>
For following XML file:
<xml>
<a b='"c"' />
<a b='"x"' />
</xml>
Produces (as I think) desired effect:
<a b='"c"'>
<a b='"x"'>