A business model which describes an enterprise and the vision of its managers is often large and complicated. BSDM has provided concise notations in order to cut down the complexity of the problem. However, one main problem still remains - how does one know that the developed model is right for the described company?In my research work, a formal logic method was developed which can be used to support a business modelling method (BSDM). Based on this formal method a framework and a knowledge based tool were created to support the development cycle for business model building. The tool supports the storage of models, report generation, automatic model verification and validation with advice provision, and automatic model pattern matching with guidance facilities. In this talk, an overview of the research will be given as well as the insights about how an informal model, such as a business model in BSDM, can be verified and validated. With those help, the managers and the modelers may now be able to say that "Now we know this model is right for us!".