1. A method of defining an application, comprising: defining a user-centric modeling component, the user-centric modeling component modeling an interactive software system and including a plurality of process steps, the plurality of process steps defining a business scenario; identifying for each process step in the plurality of process steps one or more service requirements, where a service requirement represents functionality necessary to accomplish a step; and identifying for each service requirement a process component capable of providing the service requirement, the process component modeling software implementing a business process and defining a service operation for providing the service requirement and for interacting with other process components.