Rated 5 out of 5 stars

Worked first time, very simple and very useful.
You do need to know that it works via clicking "options" under Tools > Addons> Folderpane.
Saves a lot of very fiddly and frustrating work manually tweaking the config files, and should be build into Thunderbird.

This review is for a previous version of the add-on (0.0.5.1).