In 508 mode the AActivitySpace will handle views differently. When GetView(name) is called, the space will first attempt to find the view (name + _D). It will return that if it exists, otherwise it will return the normal view, which will be responsible for displaying 508 HTML. The _D views will be only for 508 mode.
ASConstants Class | com.plumtree.uiinfrastructure.activityspace Namespace | SECTION_508