function createRecurrenceid() {
    $cnt = count( $this->recurrenceid );
    if( 0 >= $cnt )
      return;
    $formatted  = $this->_format_date_time( $this->recurrenceid['value'] );
    $attributes = $this->_createParams( $this->recurrenceid['params'] );
    return $this->_createElement( 'RECURRENCE-ID', $attributes, $formatted );
  }