Rated 4 out of 5 stars
Sorry, my English is very very poor.
I tried it today with my home PC Seamonkey 2.7.2.
In this add-on site (addons.mozilla.org) it do work, automatic found the search-item and ask to add it.
By the way, it is really work with 2.7.2.
The problem maybe Gecko Engine not really recongnize search-item very well.