Recently, Model Driven Engineering (MDE) has been proposed for supporting the development, maintenance and evolution of software systems. Model Driven Architecture (MDA), Software Factories and the Eclipse Modeling Framework (EMF) are representative MDE approaches. These MDE approaches have some concepts and techniques in common such as modeling, metamodels and model transformation. Nowadays, it is well recognized that model transformation is at the heart of MDE approaches and represents as a consequence one of the most important operations in MDE. However, despite the multitude of model transformation language proposals emerging from university and industry, these transformations are often created manually, which is a tedious and error-prone task, and therefore an expensive process. In this paper we propose, in the first part, an extended architecture that aims to semi-automate the process of transformation in the context of MDA. This architecture involves concepts and techniques of metamodel matching, inspired and borrowed from schema matching techniques that are an important issue in the database and ontology domain. In the second part, our architecture is enforced by a methodology which details the different steps leading to a semi-automatic transformation process. Matching foundations and our approach for metamodel matching are discussed. Then, we use UML and the C# platform to illustrate our approach and to evaluate our Mapping Tool for MDE (MT4MDE) and Semi-Automatic Matching Tool for MDE (SAMT4MDE).