Testing techniques in industry are not yet adapted for product line engineering (PLE). In particular, Model-based Testing (MBT), a technique that allows to automatically generate test cases from requirements, lacks support for managing variability (differences) among a set of related product. In this paper, we present an approach to equip usage models, a widely used formalism in MBT, with variability capabilities. Formal correspondences are established between a variability model, a set of functional requirements, and a usage model. An algorithm then exploits the traceability links to automatically derive a usage model variant from a desired set of selected features. The approach is integrated into the professional MBT tool MaTeLo and is currently used in industry.