Service engineering has merged to boost the development of services required by users to satisfy Quality of Service requirements. As there is a shift towards a service based economy planned to increase profit, more and more complex services are proposed by companies. At the same time customer needs due to numerous offers are ill-defined, change rapidly over the time and even does not exit on the market. The combination of existing services to build a new one is a possibility that is time consuming for the service consumer and necessitates expertise to make the combination successful. In IT, service brokers are used to provide services satisfying QoS requirements. In that paper we propose to use concepts from service engineering to define a service composition mechanism enabling the development of complex services regardless its type as well as a service delivery process modeling to support service production.