# File lib/edi4r/edifact-rexml.rb, line 101
    def to_xml( xdoc = REXML::Document.new )
      rc = super
      # Add parameter(s) to header in rc[1]
      unless @una.nil? #@una.empty?
        xel = REXML::Element.new('Parameter')
        rc[1] << xel
        xel.attributes["name"] = 'UNA'
        xel.text = @una.to_s
      end
#      rc
      xdoc
    end