function _storeDataValidity()
    {
        $record      = 0x01b2;      // Record identifier
        $length      = 0x0012;      // Bytes to follow

        $grbit       = 0x0002;      // Prompt box at cell, no cached validity data at DV records
        $horPos      = 0x00000000;  // Horizontal position of prompt box, if fixed position
        $verPos      = 0x00000000;  // Vertical position of prompt box, if fixed position
        $objId       = 0xffffffff;  // Object identifier of drop down arrow object, or -1 if not visible

        $header      = pack('vv', $record, $length);
        $data        = pack('vVVVV', $grbit, $horPos, $verPos, $objId,
                                     count($this->_dv));
        $this->_append($header.$data);

        $record = 0x01be;              // Record identifier
        foreach ($this->_dv as $dv) {
            $length = strlen($dv);      // Bytes to follow
            $header = pack("vv", $record, $length);
            $this->_append($header . $dv);
        }
    }