If you allow users to pre-order products on your site please send us order and transaction data as follows:

• $create_order should be sent when the user places the order
• $transaction (with $transaction_type: $authorize) should be sent when you authorize the card, whether this is at the time of placing the order, or could be when the release date has arrived.
• $transaction (with $transaction_type: $capture) should be sent when you capture payment, often on release date, right before product delivery.