function createAttach() {
    $cnt = count( $this->attach );
    if( 0 >= $cnt )
      return;
    $output    = null;
    foreach( $this->attach as $attachPart ) {
      $attributes = $this->_createParams( $attachPart['params'] );
      $output    .= $this->_createElement( 'ATTACH', $attributes, $attachPart['value'] );
    }
    return $output;
  }