Cloud Computing has become in just few years a key consideration for businesses and governments willing to externalize their infrastructure, increase flexibility and reduce the cost of their infrastructure (CAPEX), maintenance and operation (OPEX). Although several commercial solutions are available, there are still numerous issues to solve. Two important aspects to address are the lock-in risk with one Cloud Provider (CP) and the fulfillment of the contractual SLA (Service Level Agreement). In this paper, we propose an integrated approach based on the concept of Broker that takes benefit from different CPs to efficiently embed a complex service into the various available cloud infrastructures. The Broker approach allows Cloud Customer (CC) to be independent from any particular CP while taking benefit from the overall available resources and avoid the lock-in with a particular one. In addition, we leverage the service model to provide Customers with the possibility to request different types of services (e.g. compound service) and propose a solution to fulfill requested Customer SLA in terms of availability, cost and geographic location according to the contracted SLA between the Broker and the CPs. We have implemented the solution in a lab cloud infrastructure and performed several tests and simulations to highlight the benefit of our approach.