function DoAuthTran($ccno,
                        $expdate,
                        $cvc,
                        $orderid,
                        $amount,
                        $currency,
                        $instnumber,
                        $multpoint = "00",
                        $extpoint = "000000") {

        $posnetRequest = new PosnetRequest();

        $posnetRequest->ccno = $ccno;
        $posnetRequest->expdate = $expdate;
        $posnetRequest->cvc = $cvc;
        $posnetRequest->orderid = $orderid;
        $posnetRequest->amount = $amount;
        $posnetRequest->currency = $currency;
        $posnetRequest->instnumber = $instnumber;
        $posnetRequest->multiplepoint = $multpoint;
        $posnetRequest->extrapoint = $extpoint;
        $posnetRequest->koicode = $this->koicode;

        return $this->DoTran($posnetRequest, "auth");
    }