In the context of the POLIKOM research program novel telecooperation tools to support the distributed German government are being developed. POLITeam is one of the projects resulting from this program, aiming at the development of a system supporting cooperation in large, geographically distributed organizations. Main area of research is asynchronous cooperation, based on the metaphors of electronic circulation folders and shared electronic workspaces. The design process of POLITeam is based on the continuous improvement of an existing groupware system in close cooperation with selected pilot users. This paper discusses our methodological design approach, the design of the POLITeam system, and the experiences our application partners made in the course of using the system at work.