Agent-Based Modelling is gaining wider acceptance as a paradigm for social research. However, it still presents limitations in the management of the process to generate the simulations from the initial conceptual models. This makes it difficult to reuse the knowledge from available models and to adapt it to different hypotheses. This paper proposes the use of metamodels in order to define explicitly the core concepts of a problem domain and to differentiate the aspects involved in the process. A case study for posted pricing institutions shows how to define the related metamodel and use it to address alternative situations in these auctions. The case study drives the discussion on the advantages and limitations that metamodelling can bring to social simulation
