It would be really cool if you could enable POI for XPages to accept save thru webdav.
Back to a new or another specified document.
This would also be a great addition to OpenNTF Essentials, to get the possibility to change bookmarks and data in Excel and Word send them to the client. And when saving them back.
http://www.openntf.org/internal/home.nsf/project.xsp?action=openDocument&name=WebDAV%20for%20IBM%20Domino