Until the next version... Rated 5 out of 5 stars
To force addon compatibility in Firefox 8 you must have to:
Type about:config in Firefox addressbar and press Enter. It'll confirm, click on "I'll be careful, I promise!" button. Now right-click and select "New", then "Boolean". Give it name:
And set it's value to false. That's all.
This is the same thing that NTT does with your browser, but it always changes the version number automatically to match the browser's version. That's why I gave it five stars.