# File lib/edi4r/edifact-rexml.rb, line 119
    def to_din16557_4( xdoc = REXML::Document.new )
      externalID = "SYSTEM \"edifact.dtd\""
      doc_element_name = 'EDIFACTINTERCHANGE'
      xdoc << REXML::XMLDecl.new
      xdoc << REXML::DocType.new( doc_element_name, externalID )

      doc_el = REXML::Element.new( doc_element_name )
      xel  = REXML::Element.new( 'UNA' ) 
      xel.attributes["UNA1"]  = una.ce_sep.chr
      xel.attributes["UNA2"]  = una.de_sep.chr
      xel.attributes["UNA3"]  = una.decimal_sign.chr
      xel.attributes["UNA4"]  = una.esc_char.chr
      xel.attributes["UNA5"]  = una.rep_sep.chr
      xel.attributes["UNA6"]  = una.seg_term.chr
      xdoc.elements << doc_el
      doc_el.elements << xel

      super( xdoc.root )
      xdoc
    end