Right now, it is possible to edit a document using MS Word with WebDav, but LibreOffice use another WebDav implementation which require more dev.
To test : Go to the document module in a workspace, click on any document (odt, doc, docx, xsl, .....) and click on edit.
You should only have LibreOffice installed (if you have Microsoft Office, it will have the priority).
The document should be opened, you can modify it and save.
The save should be visible online.