it would take about five minutes to make one of the SSD semi 38s into full auto
All they have done ( see the drawing) is add a bar from the trigger ( much like the Sten mech ) and the bolt travelling forward catches this bar and re-sets the sear
all you would have to do is change the sear and trigger to sear connecting bar and brrrrrrrrp

simples !
EDIT Not that I would advocate any of the overseas owners to do such a thing , Im only talking from an engineering point of view.
plus its also one of the reasons we would never get them here ...in any calibre
DOC