Automatic or assisted workflow composition is a field of intense research for applications to the world wide web or to business process modeling. Workflow composition is traditionally addressed in various ways, generally via theorem proving techniques. The originality of this research stems from the observation that building a composite workflow bears strong relationships with finite model search, and that some workflow languages can be defined as constrained object metamodels [1], [2]. This leads to consider the viability of applying configuration techniques to this problem. Our main contribution is to prove the feasibility of such an approach, with some advantages and drawbacks compared to logical based techniques. We present a constrained object model for workflow composition, based upon a metamodel for workflows and ontologies for processes and data flows. Experimental results are listed for a working implementation that generates complex interleaving composite workflows involving transformations, synchronization and branching constructs.