Solution : https://service.sap.com/sap/support/notes/1015644 (SAP Service marketplace login required)
Key words :
'reference purchase order' field, change standard fields, relevant correction instructions, terms ekpo-refbs, purchase order, ekpo-refps, mepoitem-refbs, me_process_po badi, mepoitem-refps, if_async_subject_mm~get_changes
Related Notes :
| 1066892 | MEPO BadI - no reference when copying item within PO |
| 1023246 | IS-OIL MEPO EXCISE DUTY 2STEP TRANSFER COPY/CHANGE MODE |
| 938251 | ME21N/ME59N: Problems when copying purchase orders |