Alternative German locale

Hello,

I have a little problem with a locale. I have created an alternative
German translation for Firefox 2.0
(http://home.arcor.de/dwschneider/de-ade.xpi), but there are some
difficulties. While the alternative locale is active, the auto update
(and notification about new versions) of Firefox does not work. I
assume that the install.rdf is broken, but I have no idea how to fix
it. Therefore my question: is there any way to use Firefox with an
optionally locale without losing basic functions of the browser?

Daniel