Solution : https://service.sap.com/sap/support/notes/397379 (SAP Service marketplace login required)
Key words : 
additional key words it_sl_doc, attached source code corrections, atp field catalog, user exist 'catalog, prerequisites solution implement, apo system, /3-apo connection, sales order, integration model, transferred
Related Notes : 
       
| 390794 | |
| 375193 | Backorder processing: Composite SAP note on posting |