Solution : https://service.sap.com/sap/support/notes/426268 (SAP Service marketplace login required)
Key words :
terms sd-fi interface, created individual billing documents, individual billing documents, billing document manually, vbrk-zlsch reason, respective accounting documents, specific payment method, accounting documents, bseg-zlsch, payment method
Related Notes :
| 646470 | Invoice list: Payment method in single documents disappears |
| 85238 | SD FI: Paymt method from billing doc. is ignored |