Solution : https://service.sap.com/sap/support/notes/33846 (SAP Service marketplace login required)
Key words :
additional key words account assignment field, choose 'extras->runtime object->check', customer-defined account assignment fields, account assignment field, customer include ci_cobl, field stays empty, activate view covp, line item reports, line item report, display view covp
Related Notes :
| 43077 | Missing migr. cus.-def. acc.assgn.concepts in 3.0 |