Multi-organizational EDI message networks are complicated communication environments with various standards and technologies. The role of third party message exchange hubs has become more important and their tasks more difficult. Current development activities for supporting the utilization of XML in electronic commerce focuses on message standardization and specification of common business architectures, processes, and web practices. A need to visualize EDI messages in different contexts to human readers has received insufficient attention in ongoing activities. In this paper we discuss problems and approaches related to the visualization of EDI messages in XML format. An idea of a standardized master style sheet is described for reducing the efforts needed in the standardization and maintenance of style sheets in a hub service. We also give some recommendations for designing the master style sheets based on our experiences in participating the building of a commercial hub service. C...