This paper presents a flexible software architecture concept that allows the automatic generation of fully accessible PDF documents originating from various authoring tools such as Adobe InDesign [1] or Microsoft Word [2]. The architecture can be extended to include any authoring tools capable of creating PDF documents. For each authoring tool, a software accessibility plug-in must be implemented which analyzes the logical structure of the document and creates an XML representation of it. This XML file is used in combination with an untagged non-accessible PDF to create an accessible PDF version of the document. The implemented accessibility plug-in prototype allows authors of documents to check for accessibility issues while creating their documents and add the additional semantic information needed to generate a fully accessible PDF document.