Warehousing data is not a trivial task, particularly when dealing with huge amounts of distributed and heterogeneous data. Moreover, traditional decision support systems do not feature intelligent capabilities for integrating such complex data. Therefore, we propose an approach for intelligent decision support based on active XML warehousing. We exploit XML as a pivot language in order to unify, model and store complex data. Furthermore, Web services tackle the distribution and interoperability problems of data sources. They are employed for complex data integration and react with active rules for realizing intelligent ETL. In this paper, we focus on the integration phase and propose an architecture for integrating complex data into a repository of Active XML documents, based onWeb services and event-driven rules. We have finally developed a software prototype to validate this approach.