you shouldn't need an adapter. maybe a washer or two like when mixing brands in other occasions.
have not put these boots on a slingshot board in person,... but the boots should slide over the pegs and through the LF toothed-nut and then capped on top with the slingshot barrel nut.
not sure if that description makes sense or not. but watching this video along with it might help more http://www.youtube.com/watch?v=iIzGyijiMDA