Embedded systems are steadily growing in complexity and nowadays power consumption additionally plays an important role. Designing and exploring such systems embedded in its environment demand for holistic and efficient simulations. In this work we use a simulation framework based on the HLA (High-Level Architecture) and the modeling tool Ptolemy II to enable complex heterogeneous distributed simulations of embedded systems. In this context, we introduce a co-simulation based power estimation approach by integrating domain-specific simulators as well as off-the-shelf HDL simulator and synthesis tools. This enables cross-domain interaction and generation of realistic on-the-fly stimuli data for Register Transfer Level and Gate Level models as well as the gathering of power estimation data. We apply the framework to a Vehicle-2-X scenario evaluating an ECDSA signature processing core which ensures trustworthiness in vehicular wireless networks. To evaluate dynamic power reduction possibilities on application level we additionally introduce a V2X Message Evaluation technique to reduce signature verification efforts. It shows how realistic on-the-fly stimuli data obtained by the framework can improve the exploration and estimation of dynamic power consumption.