An automotive middleware layer masks the heterogeneity of platforms, and provides high level communication services to applicative tasks. In addition, this layer is a software architecture, shared between car makers and third-part suppliers, ensuring the portability and interoperability of the applicative tasks. In this study, a method aiming at developing the middleware's software architecture, and obtaining a set of tasks well characterized representing the middleware's implementation, is presented. This architecture is built with a set of design patterns, and identifies a set of middleware tasks whose characteristics allow the execution of an algorithm trying to determine a feasible priority allocation for the set of applicative and middleware tasks.