table.borders.with.css - doesn't allow CSS styles?

[Xmplar <info@xmplar.biz>]

I'm experimenting with 'table.borders.with.css' set to '1' in 1.77.1-ns and the styles I've set in my customization layer for border color, style and thickness are still being generated in HTML5. I would expect that when table.borders.with.css is '1', any params in my customization should be ignored, and that I would then be able to set border attributes in CSS.
My param settings are:

<xsl:param name="table.borders.with.css">1</xsl:param>
              <xsl:param name="default.table.frame">none</xsl:param>
              <xsl:param name="table.frame.border.color">#000000</xsl:param>
              <xsl:param name="table.frame.border.style">solid</xsl:param>
              <xsl:param name="table.frame.border.thickness">2px</xsl:param>
 
              <xsl:param name="table.cell.border.color">#000000</xsl:param>
              <xsl:param name="table.cell.border.style">none</xsl:param>
              <xsl:param name="table.cell.border.thickness">1px</xsl:param>
 
And typical output is:
<div
              class="table-contents"><a id="d0e1169" class="indexterm"></a><table
                style="width: 100%; border-collapse: collapse;border-top: 2px solid #000000; border-bottom: 2px solid #000000; ">
                <colgroup>...

Any border styles I then set in CSS are not overriding the values in the <table> "style" attribute. What should I be doing differently?

--
Dave Gardiner