public function saveCartOrder($rawPost)
 {
     Cart66Common::log('[' . basename(__FILE__) . ' - line ' . __LINE__ . "] Calling Cart66PayPalIpn::saveCartOrder: " . print_r($rawPost, true));
     if ($rawPost['mc_gross'] >= 0) {
         $decodedPost = $this->_decodeRawPost($rawPost);
         $paypal = new Cart66PayPalStandard();
         Cart66Common::log('[' . basename(__FILE__) . ' - line ' . __LINE__ . "] About to hit Cart66PayPalStandard::saveOrder");
         $paypal->saveOrder($decodedPost);
     }
 }
<!-- PayPal Checkout -->
<?php 
if (isset($_POST['cmd'])) {
    $paypalAction = 'https://www.paypal.com/cgi-bin/webscr';
    if (SANDBOX) {
        $paypalAction = 'https://www.sandbox.paypal.com/cgi-bin/webscr';
    }
    // store pending order with all information, then send to paypal at the above address via curl... so as to keep all the post data
    require_once CART66_PATH . "/gateways/Cart66PayPalStandard.php";
    $paypalStandard = new Cart66PayPalStandard();
    $pendingOrderId = $paypalStandard->storePendingOrder();
    $order = new Cart66Order($pendingOrderId);
    $_POST['custom'] = $order->ouid . $_POST['custom'];
    Cart66Session::set('Cart66PendingOUID', $order->ouid);
    wp_redirect($paypalAction . '?' . http_build_query($_POST, '', '&'));
    exit;
}
$taxRate = new Cart66TaxRate();
$items = Cart66Session::get('Cart66Cart')->getItems();
$shipping = Cart66Session::get('Cart66Cart')->getShippingCost();
$shippingMethod = Cart66Session::get('Cart66Cart')->getShippingMethodName();
$setting = new Cart66Setting();
$paypalEmail = Cart66Setting::getValue('paypal_email');
if (!$paypalEmail) {
    throw new Cart66Exception('Invalid PayPal Standard Configuration', 66504);
}
$returnUrl = Cart66Setting::getValue('paypal_return_url');
$promotion = Cart66Session::get('Cart66Promotion');
$checkoutOk = true;
if (Cart66Session::get('Cart66Cart')->requireShipping()) {
    $liveRates = Cart66Setting::getValue('use_live_rates');