Payment Terms (PTC) on the Purchase Order Detail

 Hi

The payment terms is available only on the Purchase Order header. We have a business requirement wherein the payment terms need to be stored at an item level because vendors have different terms for different items. The Payment terms field (PTC) is available both in the header (F4301) as well as detail (F4311) file. We have been thinking of modifying the grid to enable entering the payment terms at the detail level. Has anyone done this before? Is this a big technical challenge like modifying the master business fucntion? Does it have any impact on any other processing? Would appreciate if I