Solution : https://service.sap.com/sap/support/notes/553650 (SAP Service marketplace login required)
Key words : 
terms fp-sd-rwin, sd/fi-ca reason, fp-sd-billing, fi-ca system, fi-ar system, payment baseline date, net payment corresponds, net payment, system ignores, payment requests
Related Notes : 
       
| 180344 | SD/FI transfer of down paym.req. with payment deadline |