How can I alter the spotlight category spreadsheets to include ODS In Lion, the "All My Files" smart folder in finder is based on spotlight search categories. While I can see how from System Preferences->Spotlight->Search Results I can alter the order of these as well as enabled/disable categories, I cannot see how to alter the file types that go into them.

I specifically want to add the Libre Office ODS file type into spreadsheets, but a generalised answer I can use for other file types is even better.

I don't fear cracking out vi and editing system files.
Install "LibreOffice", latest version. It contains the aforementioned mdiimporter plugin. Confirmed just now, to be working. LibreOffice 3.5.6 on OS X 10.7.5