My Domibus message broker is already installed and running on a CentOS Stream 9 host. The next step is to make it talk reliably to the EU ICS-2 platform with XML payloads and to expose a REST endpoint so our in-house ERP can push messages straight into Domibus. Here is what I expect from you: • Configure PMode, KeyStore and Trust Store in the CONF environment, and mirror the same settings in LIVE once we are confident everything works. • Verify secure AS4 exchange with the official ICS-2 test services, then with the production gateway. • Show me—step by step—how to invoke the Domibus REST API from our ERP (token retrieval, message submission, status checks). A small working example will be enough. • Deliver a concise document covering every change you make: paths, commands, certificates, troubleshooting tips, and how to rotate keys or update PModes in the future. Acceptance criteria 1. A successful end-to-end send/receive cycle against ICS-2 in both CONF and LIVE. 2. REST calls from our ERP accepted by Domibus and visible in the monitoring console. 3. Clear, reproducible documentation I can hand to the ops team. If you have already walked through an ICS-2 onboarding, this should be mostly guidance and verification rather than hands-on installation work, and we can move quickly.