Comment 4 for bug 496768

With help from:
http://askubuntu.com/questions/55653/how-to-associate-file-extension-not-file-type-for-a-particular-application

Created "devede.xml" in "/usr/share/mime/packages" (mod 644) [file attached].
Ran `sudo update-mime-database /usr/share/mime`.
Added "application/xml-devede=devede.desktop;" to "~/.local/share/applications/mimeinfo.cache".
Ran `killall nautilus && nautilus &`.

Now, opening *.devede files causes DeVeDe to open to the "Disc type selection" dialog, but it does not load the project.

That is as far as I could get. Also, there is most likely a system-wide mimeinfo.cache file to use instead of "~/.local/share/applications/mimeinfo.cache".