function _storeOLEFile()
    {
        if($this->_BIFF_version == 0x0600) {
            $OLE = new OLE_PPS_File(OLE::Asc2Ucs('Workbook'));
        } else {
            $OLE = new OLE_PPS_File(OLE::Asc2Ucs('Book'));
        }
        if ($this->_tmp_dir != '') {
            $OLE->setTempDir($this->_tmp_dir);
        }
        $res = $OLE->init();
        if ($this->isError($res)) {
            return $this->raiseError("OLE Error: ".$res->getMessage());
        }
        $OLE->append($this->_data);

        $total_worksheets = count($this->_worksheets);
        for ($i = 0; $i < $total_worksheets; $i++) {
            while ($tmp = $this->_worksheets[$i]->getData()) {
                $OLE->append($tmp);
            }
        }

        $root = new OLE_PPS_Root(time(), time(), array($OLE));
        if ($this->_tmp_dir != '') {
            $root->setTempDir($this->_tmp_dir);
        }

        $res = $root->save($this->_filename);
        if ($this->isError($res)) {
            return $this->raiseError("OLE Error: ".$res->getMessage());
        }
        return true;
    }