The use of workflow technology to provide automated support to the management and execution of software engineering processes has become of great interest for large software companies that nowadays are moving towards the new model of "virtual" organizations. Therefore, workflow systems that allow co-operation among team members in a distributed environment are now a primary concern. In this paper we present a new WfMS, named FlowManager, which has all the potential to be used in such application domain. FlowManager, in fact, will be a component of a larger European project, named Generalized Environment for Process Management in Cooperative Software Engineering (GENESIS), whose objective is to develop a non-invasive and open source environment for modeling software engineering processes and managing co-operation among geographically distributed teams.