Distributed embedded systems implemented with mixed, event-triggered and time-triggered task sets, which communicate over bus protocols consisting of both static and dynamic phases, are emerging as the new standard in application areas such as automotive electronics. In a previous paper, we have developed a holistic timing analysis and scheduling approach for this category of systems. Based on this result, in the present paper, new design problems are solved, which we identified as characteristic for such hybrid systems: partitioning of the system functionality into time-triggered and event-triggered domains and the optimization of parameters corresponding to the communication protocol. We addressed both problems in the context of a heuristic which performs mapping and scheduling of the system functionality. We demonstrated the efficiency of the proposed technique with extensive experiments.