Maintaing Firefox preferences for all users across updates
 

To set preferences (the web proxy) for all users on all terminal server, I place a file in </usr/lib/firefox-1.0.7/defaults/pref>. However, every time a security update comes out, the version number changes, so the new Firefox doesn't see the preferences in the previous directory. Then, users cannot connect to the Internet because of the firewall. So, is there a clean, automated way to maintain preferences for all users across Firefox updates?

We are using Fedora Core 4.

If it's only proxy settings, why not supply it as a proxy.pac file?
Search LQ if you want to know more about proxy.pac, there's some threads here, it's easy.

That's what I am doing, but I how do you tell the browser to use it? By default Firefox uses "direct connection," so that's why I set a preference in </usr/lib/firefox-1.0.7/defaults/pref> to use the autoconfiguration file.

That's what I am doing, but I how do you tell the browser to use it?
See for instance Automatic proxy HTTP server configuration in web browsers. Instead of using a PAC file you could also run a post-install sed script on the prefs file, there's only two variables you need to change after all.

On which prefs file? The global prefs file is the one that I have a problem with because it's moving.