In this work we present techniques and tools that enable effective reverse engineering procedures for web applications that were developed using the promising ASP.NET technology. We deal with model-driven development in its reverse aspect by implementing reverse engineering methods. Our implemented methods model web applications using a well-known, web oriented and robust language, namely WebML. This is, to the authors' best knowledge, a novel re-engineering transformation. In this paper we propose a method to reverse engineer web applications in order to extract their conceptual model using WebML notation. Moreover, we present an efficient tool we have developed in order to implement the proposed method, along with a study of the application of our tool to an exemplar, contentmanagement web application. The overall results are quite encouraging and indicate that our approach is efficient.