The integration of customers in the process of mutual value addition (co-design process) is one of the most important aspects of mass customisation (MC). Their role as co-designers, enables customers to directly influence the development and configuration of their products. However, the necessary interaction with the provider during product development requires sufficient knowledge and expertise from customers. Customer integration capability (CIC) describes the skills a mass customiser's customers need to collaborate in interactive value adding processes in order to co-design them smoothly, effectively and to their own satisfaction. Taking these ideas into consideration, this paper analyses CIC and dependencies with other aspects of corporate value added in a causal model. The idea underlying this study is that, apart from classic tools of customer relationship management, mass customisers in particular have to foster CIC by systematic actions in order to remain internationally competitive in the long term.