Attached (at the bottom) is a script I wrote to install extensions for all users.
Save the script (or just untarball the attachment) to a file (I called it add_firefox_extensions).
Place it in a directory found with
My system is set up to look in $HOME/bin, so I put mine there.
make it executable with:
now run it for the instructions (all you need to do is pass the xpi file) and it will do all the grunt work.
Hope it helps some.
Yours,
Narnie
ps, let me know if you run into any problems.