Solution : https://service.sap.com/sap/support/notes/553211 (SAP Service marketplace login required)
Key words :
short text----------------------------------------------------------------------e_partner_ext type bu_partner, temporary partner number reason, external partner numberthen make, entered external partner number, source code additions displayed, purpose call transaction se37, external partner number, final external number, source code correction, symptom event bpnex
Related Notes :
| 564668 | Incorrect saving of BP with external number assignment |