This paper presents an engineering approach of product/service oriented value creation chains. When configuring product/service productive networks, a high variability in alternative scenarios have to be considered due to flexibility levers introduced by the service oriented approach. To cope with the difficulty of scenario selection a 2 stages engineering approach is proposed. The first stage is developed in this paper, aiming at a general analysis of alternative scenarios: a network model and an evaluation system for scenario comparison are explained and discussed.