The concept of automating Web services, specifically the brokering activities, is an active research topic. We need a comprehensive and overarching framework that seamlessly incorporates intelligent middleware agents within the context of workflow management, and addresses the issues related to Virtual Organizations. The goal is to add semantics to Web services to endow them with capabilities currently lacking in the literature, but necessary for their successful deployment in future systems. This paper discusses how the Knowledge-based Dynamic Semantic Web Services (KDSWS) Framework, interoperating with the Knowledge Sifter Architecture, can be used to dynamically broker Semantic Web Services. The Functional Agent Services Architecture of the KDSWS Framework contains Intelligent Middleware Agents to enable these dynamic operations. In particular, the specification of the roles of the intelligent middleware agents' in the brokering is presented.