In SOSE, services are composed at run time. Several mechanisms exist to compose services, such as pipe and filter which can direct the output of one service into the input of another service, orchestration and choreography. Orchestration utilizes a high-level scripting language to control the sequence and flow of service execution. It describes the behavior and interactions of a specific service provider with other involved services. BPEL4WS (Business Process Execution Language for Web Services) and WSCI (Web Service Conversation Interface) are examples of web service orchestration languages. Choreography describes the interactions between service providers that are collaborated for achieving business functionality. WS-CDL (Web Service Choreography Description Language) [24] is one example of choreography languages.