Adding Discount percent in Goods receipt PO

Hello Friends,

I am Trying to add an Goods Receipt PO document line

using oPurchaseDeliveryNotes object . It is taking all values of line except discount percent.

I want to ask is there any method to asign the discount through oPurchaseDeliveryNotes object.

I did in following way

GrPODoc.Lines.DiscountPercent=RS.Fields.Item("U_Disc").Value

Thanks & Regards,

Mithun.