Service integration and domain interoperability are the basic requirements in the development of current service-oriented e-Government applications. Semantic Web and, in particular, Semantic Web Service (SWS) technology aim to address these issues. However, the integration between e-Government applications and SWS is not an easy task. We argue that a more complex semantic layer needs to be modeled. The aim of our work is to provide an ontological framework that maps such a semantic layer. In this paper, we describe our approach for creating a project-independent and reusable model, and provide a case study that demonstrates its applicability.