The mapping problem has been defined as the way to map models involved throughout the development life cycle of user interfaces. Model-based design of user interfaces has followed a long tradition of establishing models and maintaining mappings between them. This paper introduces a formal definition of potential mappings between models with its corresponding syntax so as to create a uniform and integrated framework for adding, removing, and modifying mappings throughout the development life cycle. For the first time, the mappings can be established from any source model to any target model, one or many, in the same formalism. Those models include task, domain, presentation, dialog, and context of use, which is itself decomposed into user, platform, and environment. IDEALXML consists of a Java application allowing the designer to edit any model at any time, and any element of any model, but also to establish a set of mappings, either manually or automatically based on a mapping model.