this is how you can get it to work Rated 3 out of 5 stars

plugin very useful.

it still works, install nightly tester tools https://addons.mozilla.org/en-US/firefox/addon/6543

and that will allow you to install it from the release notes below (https://addons.mozilla.org/en-US/firefox/addons/versions/8078#version-0.4.0.6)