Viewpoint-based conceptual modeling is concerned with theidentification of a complete and coherent set of software models that have been developed with the involvement of various analysts. The contribution of multiple analysts in this process will provide a rich and comprehensive final product. One of the major concerns in any process requiring the direct involvement of human analysts is the introduction of uncertainty and inconsistency. In this paper, we employ a formal model based on belief theory that attempts to capture the degree of analysts' uncertainty towards their specifications and builds on these information to create a unique integrated model. The model is employed in the process of developing a conceptual model for the Pet Store application. The results show that the formal framework provides suitable tools for formal negotiation, belief revision, consensus building, belief recommendation and expert reliability evaluation.