I. Introduction
Workflow management systems are currently widely accepted as a necessity to provide support for complex business processes. The complexity of the processes often requires complex software. In many cases even at project start it is not entirely clear which tasks should be addressed by the workflow application. Clients often have a vague picture of the required functionality. Additionally requirements change even during software development. Business processes should address the requirements of the given application, optimize resource usage and also react to the changes and modifications.