you actually can get it to work by doing the following except without the animations. that sucks, yes, but it won't crash. I did it with a tec9 but it crashed. did it without anims and It worked. hope I helped.
You all can do the following:
Use TXD Workshop. Change the the section name "micro_uziicon" by "mp5lngicon". The DFF and TXD files called "micro_uzi", change their names by "mp5lng". And done. You ain't need anymore.
But I like this mod. This is the right SMG found in beta version!