The success of the Semantic Web crucially depends on the existence of Web pages that provide machine-understandable meta-data. This meta-data is typically added in the semantic annotation process which is currently not part of the Web engineering process. Web engineering, however, proposes methodologies to design, implement and maintain Web applications but lack the generation of meta-data. In this paper we introduce a technique to extend existing Web engineering methodologies to develop semantically annotated Web pages. The novelty of this approach is the definition of a mapping from XML Schema to ontologies, called WEESA, that can be used to automatically generate RDF meta-data from XML content documents. We further show how we integrated the WEESA mapping into an Apache Cocoon transformer to easily extend XML based Web applications to semantically annotated Web application. Categories and Subject Descriptors H.3.5 [Information Systems]: Information Storage and Retrieval; D.2 [Softw...