Component-based software development is a promising way to improve quality, time to market and handle the increasing complexity of software for real-time systems. In this paper the basic properties of an event-triggered component model for real-time software are introduced. For the early exposure of design errors a process for the simulation based validation of component-based software applying use cases is presented. A template for structuring use cases helps gathering the course-oriented requirements which describe the required behaviour of the composed software. Requirements sequence diagrams are extracted from the use cases and compared with the simulated behaviour of the component-based software. A case study of a power window control from the automotive body electronics domain demonstrates practical experience with applying use cases for the requirements validation.