The grid has emerged as a platform that enables inter-organizational internet-based collaborations in a sharing space called Virtual Organization (VO). Building a VO, in an open environment as the Internet, necessitates an access control policy to authorize, control and forbid activities in order to achieve the different partners? mutual benefits. Our goal being the dynamic VO creation is then associated with the automated generation of access control policy in a multiple access stakeholders? environment. We proposed in recent works OrBAC-based (Organization Based Access Control model) Virtual Organization model which we believe to be the corner stone in the VO creation automated process. In this paper we propose a methodology to dynamically build OrBAC-based VO and we show how our model is integrated in the creation process. The different methodology steps are explained along with the associated related works which serve for implementing our model. Finally we show an example of the model in work.