protected function buildOrder() {
        if ($this->_sortColumn == 'name') {
            $this->_selectBuilder->orderBy->add(Gpf_Db_Table_AuthUsers::FIRSTNAME, $this->_sortAsc, 'au');
            $this->_selectBuilder->orderBy->add(Gpf_Db_Table_AuthUsers::LASTNAME, $this->_sortAsc, 'au');
            return;
        }
        parent::buildOrder();
    }