Support for organization competences is an important function of Virtual Organization Breeding Environments (VOBEs), allowing VOBE members to publish and consult about the activities they may perform. In Service-Oriented VOBEs (SOVOBEs), organized systematically around the concept of services, existing competence models should be extended to support the service-orientation of SOVOBEs. In this paper, a refinement of the 4-C competence model is presented. The main enhancements consist of 1) the redefinition of the concept of a service as regards competences 2) a clear distinction of the relations between activities, services, capabilities and competences, and 3) the introduction of contextual capabilities.