Solution : https://service.sap.com/sap/support/notes/528770 (SAP Service marketplace login required)
Key words : 
create function modules ibapi_alm_order_oper_del_exs, status dsex 'date set, order bapi reason, source code corrections, date field directly, function module documentation, chapter external scheduling, status prevents, restriction set, date fields
Related Notes : 
       
| 736204 | Notes for downgrade kit ALMBAPI I | 
| 708508 | Downgrade BAPI_ALM_ORDER_MAINTAIN -> errors |