1. A method of providing layout information to be used in generating a display of data in a graphical user interface by storing schema definitions in an XML Schema Definition (XSD) schema, the method comprising: in a computer system that is configured to contain a repository of schema definitions according to UN/CEFACT Core Components Technical Specification (CCTS) for several data components, storing, within a schema definition for a data component from the repository of schema definitions for data components, layout information for the data component, each of the data components configured for defining semantics, according to CCTS, of portions of data included in an electronic communication from a sending business entity received at a receiving business entity, the electronic communication including a portion of data associated with the data component that specifies semantics of the portion of data according to CCTS, the layout information comprising XHTML, XFORMS, XSLT, or XSL-FO to define a visual appearance of the portion of data when the portion of data is presented to the receiving business entity, the visual appearance including at least one user interface element for presenting the portion of data; and outputting, for display, the portion of data with a visual appearance defined by the layout information.