This paper reports our work on extending the OMNeT++ INET Framework with a directional radio model, putting a special emphasis on the implementation of asymmetrical communications. We first analyze the original INET radio model, focusing on its design and components. Then we discuss the modifications that have been done to support directional communications. Our preliminary results show that the new model is flexible enough to allow the user to provide any antenna pattern shape, with only an additional reasonable computational cost. Categories and Subject Descriptors C.2.1 [Network Architecture and Design]: Wireless Communications; I.6.3 [Model Development]: Modeling methodologies General Terms Design, Verification, Performance Keywords OMNeT++, INET Framework, Directional Radios, Asymmetrical communication