Solution : https://service.sap.com/sap/support/notes/300027 (SAP Service marketplace login required)
Key words : 
additional key words omsl, save alphanumeric material numbers, sales order correctly, customer material number, material number, incorrect material, symptom creation, delivery orders, scheduling agreements, system positions
Related Notes : 
       
| 443574 | SD-EDI: Problems with material number |