Many Embedded Systems are supposed to run continuously, which includes recovering from errors by adapting their configuration or their architecture to changing conditions in their environment. The design of such systems has to relate some high-level extra-functional properties to some low level ones such as memory or CPU consumption by defining some complex feed-back loops for the dynamic adaptation of the system. However, although feed-back loops (also known as ``adaptation policies'') are a well-known idea, the design phase does not deal with those feed-back loops and thus the needed sensors and actuators are hard-coded during the development phase. This leads to expensive roll-back operations in the design process. To avoid that, we suggest a model-driven process based on new executable meta-modelling techniques. At modelling time, designers have to complement the architectural description with some sensors and actuators related to the involved extra-functional properties. It allows designers to specify in a consistent way the related adaptation policies. Then, since the models are executable, some simulations of the adaptation policies can be performed at design time to evaluate their performances with respect to some relevant test scenarios.