Mass customization has become a reality, and is implemented in many industries such as the shoe industry. Even though much work has been achieved until now in developing the tools and methodologies to support such a strategy, a lot has still to be done such as determining the customer order decoupling point (CODP) which is the breaking point between productions for stock based on forecast and customization based on customer demand. In this article, and under the European project DOROTHY, we propose the use of value network modeling and simulation for determining the position of the CODP based on its influence on the overall generated value of the MC system. Only the value network model as well as the modelling language and the general approach will be presented.