How to link the Manual Shipment (Shipment source = i) with the Purchase order line

Hi,

While creating manual shipment(Shipment Source = i) from P4915 for the purchase order, in Shipment Detail screen (P4915_W4915C) we can enter the Item, Quantity, Order number, Order Type & Order Company but Line number field is protected.

Please let me know whether it's possible to enter line number for the order or is there a way to link the manual shipment which was created with the correct purchase order line.

Thanks a lot !