Autonomic Communication is a new paradigm for dynamic network integration. An Autonomic Network crosses organizational boundaries and is provided by entities that see each other just as business partners. Policy-base network anagement already requires a paradigm shift in the access control mechanism (from identity-based access control to trust management and negotiation), but this is not enough for cross organizational autonomic communication. For many services no partner may guess a priori what credentials will be sent by clients and clients may not know a priori which credentials are required for completing a service requiring the orchestration of many different autonomic nodes. We propose a logical framework and a Web-Service based implementation for reasoning about access control for Autonomic Communication. Our model is based on interaction and exchange of requests for supplying or declining missing credentials. We identify the formal reasoning services that characterise the problem and sketch their implementation.