We present an approach to partitioning and mapping for multicluster embedded systems consisting of time-triggered and eventtriggered clusters, interconnected via gateways. We have proposed a schedulability analysis for such systems, including a worst-case queuing delay analysis for the gateways responsible for routing inter-cluster traffic. Based on this analysis, we address design problems characteristic to multi-clusters: partitioning of the system functionality into time-triggered and event-triggered domains, and mapping of processes onto architecture nodes. We present a branch-and-bound algorithm for solving these problems. Our algorithm is able to find schedulable implementations under limited resources, achieving an efficient utilization of the system. The developed algorithms are evaluated using extensive experiments and a real-life example.