Solution : https://service.sap.com/sap/support/notes/182555 (SAP Service marketplace login required)
Key words : 
additional key words ordchg, edi incoming orders, inbound processing terminates, prerequisites implement note 132949, function module idoc_input_ordchg, solution implement, material number, length set, transaction omsl, orders01 - orders03
Related Notes : 
       
| 150214 | EDI ORDERS: problems w numerical material number | 
| 132949 | Conversion exit MATN1 |