Symptom
Unable to display custom field in PO reference item tab in App Create Supplier Invoice - Advanced (MIRO).
Environment
SAP S/4HANA Cloud Public Edition
Cause
This is standard system design.
Resolution
Custom fields of the Business Context Procurement: Supplier Invoice Item with Purchasing Document Ref. / Consignment (MM_SI_ITEM) can be currently added to the fiori app Create Supplier Invoice only. In the GUI app Create Supplier Invoice - Advanced App the available business context is Procurement: Supplier Invoice Header.
Keywords
MIRO, Create Supplier Invoice - Advanced, Create Supplier Invoice, Custom field, MM_SI_ITEM, Purchasing Document Ref., PO reference item, invoice item
SAP Knowledge Base Article - Public