I had understood that a SEI could have multiple methods and the correct method is chosen according to the SOAPAction HTTP Request Header.
I am using a Java first approach where I have a SEI with 2 operations and both operations share the same message. So when I try two requests, each with different SOAPAction HTTP Header, both requests are handled by the same method operation.
WSI-BP states that operations need to be unique within the soap:body. However, I still think CXF should route it to the correct method.