3526567 - What information should be provided for updating missing Fields in Custom Mapping tool structure for IES integration ?

We are using the SAP Integration Suite, managed gateway for spend management and SAP Business Network to integrate SAP S4HANA with SAP Ariba Applications using IES scenarios like 42K, 2NV, 4BL etc. We added custom fields in S4HANA but same not showing up Mapping tool structure. How can we extend the mapping tool structure to perform the custom mapping logics?

missing Fields in Custom Mapping tool structure for IES integration, Extrinsic node, Custom field unavailable in mapping tool, CIG Custom mapping for S4HANA integration , KBA , BNS-ARI-CI-CUST , Managed Gateway for Procurement Custom Map (XSLT) , How To