DFF for Item tab called AML

Summary:

I am trying to add DFF to an Item's tab called AML, subtab Item AML. This is where you connect a Manufacturer to an item through a Manufacturer Part. In this case, our Item is a raw material part, and the Manufacturer Part represents the manufacturer's number for the raw material we are purchasing. We would like to add fields unique to this relationship, which is not just part of the raw material, but that raw material from that specific manufacturer.

I believe I found a document addressing this feature, so I think it is possible. However, following the document did not work for me. This is the document: https://docs.oracle.com/en/cloud/saas/supply-chain-and-manufacturing/25b/faipr/configure-descriptive-flexfields-for-approved-manufacturers-list.html