public function update(Kwf_Model_Row_Interface $row, $rowData)
 {
     $pk = $this->getPrimaryKey();
     if (isset($row->{$pk})) {
         $rowData = $this->_client->rowSave($row->getCleanDataPrimary(), $rowData);
         $this->_data[$row->{$pk}] = $rowData;
         foreach ($rowData as $k => $v) {
             $row->{$k} = $v;
         }
         return $rowData[$pk];
     }
     throw new Kwf_Exception("Can't find entry");
 }