This paper describes SOAcom, a communication model as well as a development process to characterize and adapt automotive network protocols to Service-based Driver Assistance Systems (DAS). Future DAS for articulated vehicles like a car with a caravan are characterized by a dynamic software and hardware architecture. In these systems Service-orientation is a promising approach. One major demand to be able to deploy such systems in an automotive environment is the ability to allow Service communication through the specialized automotive networks. This paper describes a development process to define a communication model that is built up by mechanisms which are necessary to allow this Service communication. The development process, consisting of four phases, is tested by defining a communication model for a Service-based DAS on the Controller Area Network (CAN). The result is then evaluated by means of a set of experiments.