request delivery date in sales order

hi,

if customer request delivery date to their site on 30/11/09, and the production should be finished before 15/11/09 and the rest of date is for shipment. Which mean the production order or purchase order should based on 15/11/09. how can i do this in sales order? should i input the request delivery date on 15/11/09. if yes, how to record the date of 30/11/09. pls advice. thanks