The management of inter-organisational business processes is a crucial and necessary factor towards the economic success of an enterprise. Flexibility and manageability of processes are core requirements to interoperability. In the article, we discuss the two complementary paradigms of the service-oriented approach and of the process-oriented approach. We demonstrate how the combination of these two concepts can be used to realize flexible and manageable processes even in a cross-enterprise scenario. The main advantage of this approach is the ability to compose business processes in a flexible way without losing the instruments of an effective business process management.