Solution : https://service.sap.com/sap/support/notes/867170 (SAP Service marketplace login required)
Key words :
transaction miro 'enter incoming invoice', invoice item line, purchase order converted, local currency, foreign currency, system displays, posting date, fi_trans_date_derive badi, terms mir7, fi_derive_wwert reason
Related Notes :
| 885976 | MIRO: Change doc type w/o calling BADI FI_TRANS_DATE_DERIVE |
| 574583 | MIRO: BADI for value date |