Solution : https://service.sap.com/sap/support/notes/530448 (SAP Service marketplace login required)
Key words : 
user exits procedures designed, solution generally consulting notes, customer-specific business processes, involves consulting solutions, sap standard system, user exits, consulting notes, standard system, business processes, sap notes 381348
Related Notes : 
       
| 520748 | SIS: Update for GI for scheduling agreements | 
| 381348 | Using user exit, customer exit, VOFM in SD | 
| 203266 | SIS setup:Val.fields in deliv., MCLIPS-AP* fields | 
| 170183 | |
| 125763 | SIS: Collective note - component supplier | 
| 69487 | VIS: Updating open order quantity for goods issue | 
| 66858 | SIS: Updating 'Number of orders' | 
| 19295 | SIS: Updating even rejected items |