Julio
When you build your data source this way, you can use the built in Excel exporter. Choosing data source of Association prevents you from using the built in Excel exporter.
Mike
Thanks Mike, That worked! I've also noted that this limitation has been resolved in version Mendix 4.3: http://www.mendix.com/tech-blog/release-announcements/new-goodies-for-mendix-app-platform-users-mendix-business-modeler-4-3-release-today/