Preprint of paper published in: TAIC PART 2008: Testing: Academic & Industrial Conference, Practice and Research Techniques, 29-31 August 2008; doi:10.1109/TAIC-PART.2008.14 Maritime Safety and Security systems represent a novel kind of large-scale distributed component-based systems in which the individual components are elaborate and complex systems in their own right. Two distinguishing characteristics are their ability to evolve during runtime, that is, joining and leaving of components, and the need for high reliability of the system. In this paper, we identify the challenges that will have to be addressed, given the current state of the art in component-based software engineering in order to build such system-of-systems. In particular, we highlight the specific difficulties regarding acceptance and testing. A first group of testing challenges is raised by the need of accepting the integration of such large systems, and the ability to reconfigure them at runtime. A second group of testing challenges comes from the fact that, generally, not all the sub-systems are designed along the same kind of architecture (e.g. client-server vs. publish-subscribe architecture). Devising an integration testing process for such hybrid architecture is inherently harder than for a homogeneous one.