Solution : https://service.sap.com/sap/support/notes/426039 (SAP Service marketplace login required)
Key words : 
additional key words bop, prerequisites note 400662 solution change, reference typeit_sl_vbxdata                              vbx_s_datait_sl_vbxhead                              vbx_s_headwith, syntax error appears, it_sl_vbxdata cif_vbxsdait_sl_vbxhead cif_vbxshe, reference structure, reference type, function modulescif_sl_doc_inbound_30acif_sl_doc_inboundcave_sl_doc_inboundcave_sl_doc_inbound_bopby, transaction se37, note 400662
Related Notes : 
       
| 426120 | Backorder processing: Changing short description | 
| 400662 | Backorder processing: Configuration characteristics | 
| 375193 | Backorder processing: Composite SAP note on posting |