Reference Columns Not Displaying AP Invoice Numbers in Actuals Folder - Account Inquiry

What reference column contains the Accounts Payable invoice number in Account Inquiry?

Account Inquiry

Account Inquiry Reference 3 displays Document number

To display invoice number:

1. Click Search or (Seg)ment Find
2. Enter [account information]
3. Accept
4. Actual (Memo) folder
5. Double-click API Journal line or click Detail in ribbon

The Invoice number is displayed in on the invoice in Invoice Inquiry. 

Ref3 column displays Document number.

The Document number on an invoice is unique, so this is the value displayed in the journal reference field.