I trust by "real-time" you are not referring to "hard" real-time systems. Hard real-time systems cannot tolerate the latencies inherent in most middleware systems. I assume you are referring to "live" integration with running applications.
Conceptually, the SCA component model provides an abstraction layer between service components and the protocols they use to communicate. Conceivably, an SCA component could interact with a legacy application using the legacy application's native protocol (assuming the SCA container provides a binding for the legacy protocol). But the reality is still a little short of the concept. Few SCA implementations exist, and the ones that do typically support a very limited set of protocol bindings (e.g., SOAP, RMI, and JMS; one implementation supports Jini).
