the Checkout form on your site will use PayPal Direct payments, when the click the checkout with paypal button on the checkout page, this is using paypal express.
for direct payments:
open the confirm page, then go to the bindings panel, click the plus button and select eCart -> Checkout -> Local Checkout response. AFrom the gateway list, select "PayPal Direct Payment"
on the server behaviors panel, double click the store order summary behavior, then bind the orders.OrderTrackingNumber column to the transaction ID binding in the Local checkout response (PayPal Direct Payment) binding group.
For Express checkout it's very similar, except you will use the pp_confirm page. when adding the local checkout response binding group, select the "Paypal Process Express Checkout" option from the gateway list.
on the server behaviors panel, double click the store order summary behavior, then bind the orders.OrderTrackingNumber column to the transaction ID binding in the Local checkout response (Process Express Checkout) binding group.
