This article describes and reflects our experiences as researchers in a design-based research project on a curriculum innovation focused on meaningful, co-operative learning in vocational education in the Netherlands. The project was successful in gaining insights in possible practices for workplace learning but did only partly realize the individuation aims formulated for the participating students. Among the reasons for this are the complexity of the project (having different types of schools participating) and the desired outcomes formulated by the financing authorities (somewhat contradicting the original goals of the originators). Mainly, however, this study reflects on the authors' contribution as researchers: it succeeded only partially in helping the project keep focus on the individuation aims. This study inquires into the causes and suggests that at the start of design-based research projects a profound analysis of the project structure and power relations and negotiations aimed at realizing conditions for real partnership are necessary. Also, one should not under-estimate the amount of time and involvement required of researchers.