Solution : https://service.sap.com/sap/support/notes/803647 (SAP Service marketplace login required)
Key words : 
change sales area specific data, terms bp_api reason, attached correction instructions, change pointer, table but000, fields chusr, solution implement, support package, correction, prerequisites
Related Notes : 
       
| 875249 | BAPIs does not trigger Bdoc (Correction to the note 803647) |