As computation and services are pervading our working and living environments, it is important for researchers and developers to have tools to simulate and visualize possible executions of the services and their compositions. The major challenge for such tools is to integrate highly heterogeneous components and to provide a link with the physical environment. We extend our previous work on the RuG ViSi tool , in a number of ways: first, we provide a customizable and interactive middleware based on open standards (UPnP and OSGi) ; second, we allow any composition engine to guide the simulation and visualization (not only predefined compositions using BPEL) ; third, the interaction with simulated or physical devices is modular and bidirectional, i.e., a device can change the state of the simulation. In the demo, we use an AI planner to guide the simulation, a number of simulated UPnP devices, a real device running Java, and a two room apartment. The related video is available at http://www.youtube.com/watch?v=2w-UIwRqtBY.