Ontologies are structured data models used to describe a set of concepts related to a specific domain, they describe also the semantic properties of these concepts. Formal development process aims to develop a system with respect to properties or constraints. The IMPEX project is interested in involving domain constraints as soon as possible into formal development process, it proposes to integrate the ontologies descriptions in an Event-B development process. This approach assumes to develop a transformation step of the ontologies constructs from their initial description in an ontological language (OWL, OntoML ...) to Event-B. A first version of this transformation approach for OWL ontologies based on a generic and extensible architecture has been developed, it is supported by the OntoEventB tool. An evolution of this approach to include OntoML ontologies and new features is presented in this paper.