How to send requester email address to/through supplier punchout site

We need to use Supplier punchout Direct punchout (cXML) to connect to a supplier. That supplier needs to be able to receive an email address for the requester(s). As it is right now, the supplier is not receiving the requester's email address.

We see the "Send optional user and company information.." option when selecting a different type of Supplier punchout - Direct punchout (Oracle native XML) - but our supplier needs cXML and says all their other Oracle customers are able to provide this information.

Please let us know if there's some patch to fix this, or that allows us to see the "Send optional user and company information" option when creating a Direct cXML punchout, if that is indeed the fix.