The agility to collaborate in several business networks has become essential for the success of enterprises. The dynamic nature of collaborations and the autonomy of enterprises creates new challenges for the operational computing environment. This paper describes the web-Pilarcos B2B middleware solutions for managing the life-cycle of dynamic business networks in an inter-enterprise environment. The use of B2B middleware moves the management challenges away from the individual enterprise applications to more global infrastructure services, and provides a level of automation into the establishment and maintenance. The middleware services aim for a rigorous level of transparent interoperability support, including awareness of collaboration processes, and collaboration level adaptation to breaches in operation.