Turning off table side borders

I've added the following to my customized layer (I realise it's overkill, but I'm not sure of the relationship between table.properties and table.table.properties, or if table.cell.properties overrides them or is overridden by them):

<xsl:attribute-set name="table.table.properties">        
       <xsl:attribute name="border-right-style">none</xsl:attribute>        
       <xsl:attribute name="border-right-width">0pt</xsl:attribute>        
       <xsl:attribute name="border-left-width">0pt</xsl:attribute>        
       <xsl:attribute name="border-left-style">none</xsl:attribute>
</xsl:attribute-set>

<xsl:attribute-set name="table.cell.properties">        
       <xsl:attribute name="border-right-style">none</xsl:attribute>
        <xsl:attribute name="border-left-style">none</xsl:attribute>
        <xsl:attribute name="border-right-width">0pt</xsl:attribute>
        <xsl:attribute name="border-left-width">0pt</xsl:attribute>
</xsl:attribute-set>

<xsl:attribute-set name="table.properties">        
        <xsl:attribute name="border-right-style">none</xsl:attribute>
        <xsl:attribute name="border-left-style">none</xsl:attribute>
        <xsl:attribute name="border-right-width">0pt</xsl:attribute>
        <xsl:attribute name="border-left-width">0pt</xsl:attribute>
</xsl:attribute-set>

Overkill or not, in any case, in PDF output tables still has side borders. Can anyone tell me where I'm going wrong?

Thanks,

P.