XP has one weakness when it comes to complex application domains or difficult situations in the customer's organization: The customer role does not reflect the different interests, skills, and forces with which we are confronted in development projects. We propose splitting the customer role into a user role and a client role. The user role is concerned with domain knowledge; the client role defines the strategic or business goals of a development project and controls its financial resources. It is the developers' task to integrate users and clients into a project that builds a system according to the users' requirements while at the same time attaining the goals set by the client. In addition, we present document types from the tools-and-materials approach [Lilienthal+1997]) that help developers integrate users and clients into a software project. All document types have been used successfully in a number of industrial projects together with the well-known XP practices.