Trusted semantic Web services might play a key role in the Future Internet. In this paper, we describe WSTO our comprehensive trust based framework supporting the selection and invocation of semantic Web services. Our framework combines the Web Services Modelling Ontology (WSMO) with a classification framework developed in the IBROW project. Our approach is generic enough to be able to account for a wide variety of trust models including those based on security, policy and end-user recommendations. Expanding on earlier work within this paper, we describe the model in detail.