Solution : https://service.sap.com/sap/support/notes/359646 (SAP Service marketplace login required)
Key words : 
additional key words shopping basket, multiple account assigned items, attached source code corrections, bbp shopping basket, /3 backend purchase orders, source code, account assignment, purchase order, bbp release 2, error occurs
Related Notes : 
       
| 503196 | Enterprise Buyer 3.5 Installation: Composite Note | 
| 409263 | Enterprise Buyer 3.0 Installation: Composite Note | 
| 360142 | Enterprise Buyer 2.0 Installation: Composite Note |