XSLT Sort by publicationDate with Time

Questions
1

I am sorting news article documents, by publicationDate, but I would like them to also be sorted by the time within the publicationDate, so the most recently published articles, that are published on the same date, would be at the top of the list. Here is what I have currently, what additions, could make this work?

<xsl:for-each select="$currentPage/descendant::NewsArticle[string(@id) != string($currentPage/featuredArticle) and string(umbracoNaviHide) != '1' and string(featureThisArticle) = '1' ]">
  <xsl:sort select="publicationDate" data-type="text" order="descending" />
<!--	<xsl:sort select="publicationDate" order="descending" /> -->
  <xsl:if test="position() &lt; 8">
    <xsl:copy-of select="." />
  </xsl:if>
</xsl:for-each>
This is a companion discussion topic for the original entry at https://our.umbraco.com/forum/72854-xslt-sort-by-publicationdate-with-time