Day of the week formatting in email confirmation

Hi,

How to format day of the week in the email confirmation ?  Currently formatting for Date only has 'year','month,'day'.

<!-- format date time values -->
  <xsl:template name="FormatDate">
    <xsl:param name="DateTime"/>
    <xsl:variable name="year">
      <xsl:value-of select="substring($DateTime,1,4)" />
    </xsl:variable>
    <xsl:variable name="mo">
      <xsl:value-of select="substring($DateTime,6,2)" />
    </xsl:variable>
    <xsl:variable name="day">
      <xsl:value-of select="substring($DateTime,9,2)" />
    </xsl:variable>

Thanks,

Sabina