[Request] Special user-exit we need during creating purchase order

Hi, Gurus!

We need to make specific User-Exit during creating Purchase order.

When user creates/change a PO document (ME21N/22N), SAP has to check the u2018CUSTOMERu2019 filed whether it is BLANK or NOT in Delivery Address tab at ITEM LEVEL.

If there is no value in that field, system will automatically input right value with useru2019s business logic.

Thatu2019s what we want to implement in the future.

If you have any solution or recommendation for this, Please help us.

I really appreciate your help in advance.

Best Rgds;

Ian