This work addresses conceptual modeling and automatic code generation for Rich Internet Applications, a variant of Web-based systems bridging the gap between desktop and Web interfaces. The approach we propose is a first step towards a full integration of RIA paradigms into the Web development process, enabling the specification of complex Web solutions mixing HTTP+HTML and Rich Internet Applications, using a single modeling language and tool. Categories and Subject Descriptors: D.2.2 [Software Engineering]: Design Tools and Techniques, computeraided software engineering (CASE), evolutionary prototyping, user interfaces; H.4.0 [ Information Systems Applications]: general; H.5.4 [ Information Interfaces and Presentation]: Hypertext / Hypermedia architectures, navigation, theory, user issues. General Terms: Design.