The Service Oriented Architecture (SOA) adoption has been enabling the raise of business networks in which each partner gets automatically the information needed to achieve maximum efficiency. When there is more than one partner providing the same service on a business network, comes the challenge of determining which one is best suited to receive a given request. This dissertation presents a software architecture and a prototype implementation that allows the definition of complex criteria to service mediation, based on both technical (availability, response time) and functional data (price, reputation, geographical location, etc.). Our goal is to explore the practical aspects of this mediation, the technologies used and the solution flexibility.