FC3 uses udev, so the /dev is generated on-the-fly, it is not a real directory. So, the change that you will make to this directory will disapear on reboot, it is just normal.
Take a look in /etc/udev.d, you should have a directory named "rules" or something similar. This is were you have to put your own "rules" you want to see applied to /dev files. I am not in front on a linux computer right now so I can't post an example, take a look first, it is a bit complex but you may be able to guess the syntax taking a look what is currently in the file.
If you can't figure this out, tell me, I'll post an example...