1. A composite application modeling system comprising at least one memory storing a composite application modeling tool and at least one processor executing the application modeling tool to perform operations, the operations comprising: processing at least one input 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; processing at least one input 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; processing at least one input identifying for each service requirement a process component capable of providing the service requirement, the process component modeling software implementing at least one process and defining a service operation for providing the service requirement and for interacting with other process components, each process component belonging to exactly one deployment unit and comprising a pair-wise interaction with another process component in another deployment unit, each deployment unit characterizing independently operable software deployable on a separate computer hardware platform; and generating at least one process component interaction model with a plurality of identified process components.