Traditional distributed embedded systems are configured using static environment information and thus do not support dynamic behavior of the system. The necessary flexibility in the system may be provided by the Flexible Time-Triggered (FTT) communication paradigm. If, in addition, it is required that the system operates continuously, the suitable fault tolerance mechanisms that provide high reliability have to be developed and deployed in the system. To be able to successfully assess those mechanisms, it is reasonable to develop simulation models that support injection of various types of faults. This paper describes an OMNeT++ simulation model for distributed systems that are based on the Hard Real-Time Ethernet Switching (HaRTES) implementation of the FTT paradigm. The contribution of the paper is twofold. First, we provide a library of components that are required for modeling FTT networks with arbitrary number of FTT slaves connected to a HaRTES switch, and second, we used the developed components to build an FTT system that is suitable for assessing some of recently proposed mechanisms for tolerating certain transient faults in the communication channel.