firefox system wide settings: A4 or Letter

[Erik Sjölund]

On Fedora Core 6 there doesn't seem to be any standard configuration
file for firefox 

$ rpm -qc firefox | wc -l
0

I succeeded changing the system wide setting for the default paper size 
to A4 by creating a new file:

# cat /usr/lib/firefox-1.5.0.9/defaults/pref/erik.js
pref("print.postscript.paper_size", "a4");

Creating a new user and starting up firefox showed that the default
paper size had indeed changed.

But hardcoding the version number into the the path doesn't seem like an
optimal solution. 

Does anyone have a better idea?

cheers,
Erik Sjölund