This worked with partially RH9, I don't know with Fedora.
mv default-modules.conf default-modules.conf.no-menu-edit
cp default-modules.conf-with-menu-edit default-modules.conf
Now you can edit the menu by going to applications:/// in Nautilus.
They disable this by default for some reason. I found that I had to restart gnome for the changes to take effect, and that gnome sometimes crashed with no apparent reason, so maybe thats why the disabled it...
I hope this helps