Business process modeling and Implementation have been longstanding activities in many corporations in recent years. Most internal processes have been streamlined and optimized, whereas the external processes have only recently become the focus of business analysts and IT middleware providers. The full integration of all processes within a supply network is an upcoming challenge that has to be addressed by network partners and solution providers. The static integration of inter-enterprise processes as common in past years can no longer meet the new requirements of customer orientation, flexibility and dynamics of cooperation. A dynamic integration of processes becomes mandatory, which is obviously much harder to achieve. A major prerequisite for dynamic integration is the reliability and flexibility of the processes involved. Although companies will work together and might even form what is known as a virtual enterprise, they will usually not reveal the details of their internal processes to each other. Furthermore, even integrated business processes are subject to change, i.e., a company commits itself to providing a process with a certain input and result, but still wants to retain the freedom to internally reorganize and optimize its processes as necessary. Consequently, traditional business process modeling techniques fail to describe loosely coupled business processes, the structure of which is opaque or completely hidden. New modeling methods are sought that allow the challenges of reliability and flexibility to be addressed.