In recent years, several model-driven proposals have defined user interface models that can represent both behavioural and aesthetic aspects. However, the software industry has ignored the majority of these proposals because the quality of the rich user interfaces generated out of these models is usually low and their code generators are not flexible, i.e., the UI templates cannot be customised easily. Furthermore, these proposals do not facilitate the separation between the visual design of the UI, normally performed by graphic designers in the industry, and the visualisation of data, which has been previously modelled using another domain-specific language. This paper proposes a new textual domain-specific language called XANUI, which could be embedded in XML-based UI pages, e.g., HTML or XML. The designed language provides the mechanisms to bind visual components with data structures already existing, and to define the behaviour of these components based on events. In this paper, XANUI is integrated in two OOH4RIA development processes, i.e., the traditional data-intensive and the new design-first process, thus reusing the OOH4RIA models and transformations to generate a complete rich Internet application for any platform or device. In order to validate this approach, the XANUI solution is applied to the development of a RIA with two UI types: a) the administration view of a Web application using HTML5 and AngularJS, and b) a catalogue application for e-Commerce using Windows RT in a Tablet PC.