tanks Mimika ! Rated 5 out of 5 stars

Mimika, your suggestion helped me to solve ! to be clear actually my xpi was in different location due to my configuration and - unfortunately - with different name (like other xpi but not all) (in this case the name was "{61A64500-335C-418D-8FCB-E072A9ABF3DA}.xpi")

This review is for a previous version of the add-on (0.8.35).  This user has a previous review of this add-on.