I managed to make it work. You'll have to cut out three screw hole/posts on both sides of the guns shell to make room inside....
I have tried to do this to my NF EX-3 but it doesnt fit when I try to put it all back together.
Is the inside of the new NF alittle different then the original one?
Also, make sure that there's enough room under the original barrel of the NF to accomodate the SSPB...and be sure to cut enough plastic from the bottom to make room for the trigger.
I'm gonna tinker with mine somemore, so I'll take pictures and put them up a bit later.