Solution : https://service.sap.com/sap/support/notes/441907 (SAP Service marketplace login required)
Key words :
change user-defined fields, additional key words me22n, order item data, enjoy purchase order, attached program corrections, program error, bapi bapi_po_change, bapi_po_change, extensionin, extensionout
Related Notes :
| 410491 | BAPI_PO_CREATE1: Customer enhancements incorrct from 2. item |
| 390742 | Customer enhancements not transferred |
| 323152 | Enjoy BAPI: Implementation of customer enhancements |