Ha, thanks to rovin for pointing me to this article: "... Microsoft announced [that] ... Office 2007, Service Pack 2 will add native support for OpenDocument Format (ODF) 1.1, ...".

I bet that will make it a lot easier to implement the Belgian directive for ODF exchanges between federal agencies. Also, it will make it a lot easier for me to convince partners to communicate with me in a ODF file format :-) (and not in .docx that I recently had to refuse)