Solution : https://service.sap.com/sap/support/notes/418581 (SAP Service marketplace login required)
Key words : 
created additional key words transaction, solution source code correction, additional delivery schedule, materials staging date, requested delivery date, desired delivery date, /sapapo/bop_updatebackorder processing, /sapapo/bop, /sapapo/bop_result, order items
Related Notes : 
       
| 416762 | Backorder processing: TP/VS scheduling incomplete | 
| 375193 | Backorder processing: Composite SAP note on posting |