Punchout Catalog – Support for HTTP Basic Authentication

We have a supplier with the following Punchout authentication requirements:

Standard cXML Punchout credentials (Domain, Identity), which is already configured.
In addition, the supplier requires HTTP Basic Authentication at the transport level.
The HTTP Basic Authentication credentials are separate from the cXML Punchout credentials and are intended to replace IP allowlisting.

Our Oracle Fusion Procurement environment receives HTTP 403 Forbidden when connecting to the supplier's Punchout site.

Our question is:

Does Oracle Fusion Procurement support sending an HTTP Authorization: Basic header independently of the cXML Punchout credentials?

If yes:

Where is this configured?
Is there any Oracle documentation describing this setup?