Web services are an important series of industry standards for adding semantics to web-based and XML-based communication, in particular among enterprises. Like the entire series, the security standards and proposals are highly modular. Combinations of several standards are put together for testing as interoperability scenarios, and these scenarios are likely to evolve into industry best practices. In the terminology of security research, the interoperability scenarios correspond to security protocols. Hence, it is desirable to analyze them for security. In this work, we analyze the security of the new Secure WS-ReliableMessaging Scenario, the first scenario to combine security elements with elements of another quality-of-service standard. We do this both symbolically and cryptographically. The results of both analyses are positive. Joint work with Michael Backes, Sebastian Moedersheim, Birgit Pfitzmann.