bah, i messed up the shirt part....
Found a little mistake that might have caused this to fail.
You accidently have snapped 2 faces together on the fat shirt mesh, under the armpit
In side view you can see that the faces of the left and right side of the mesh dont match, they cross eachother.

test this file first ingame, dont have more time right now.....
Redid the fatmorph(duplicated the basemesh and used your old fatmorph as reference, exept the snapped faces) and mapped all the parts, very roughly
You need to extract the meshes and move scale the parts on the uvmap

Got it. Thank you one more time I hope this time I will able to finish it

P.S. I owe you a beer (joke)

Seen it ingame and the sliders work, with a few little errors that you might want to fix.
You got to move your parts on empty spots on the uvmap, then fix the outer coordinates on the shirt part(otherwise the textures are stretched to much)
Think you can do the rest yourself.

Want to thank you also as i think regrouping diffrent parts of the morphs might work if you weld them together,split them up to reuvmap, then regroup into one.
Still need to do some more testing.

Yes, I can do it myself But I would like to know if the normal map will work, cause if not, then I just wont bother making it

A normalmap will work, just make sure you load it in all lods.
You load one texture and link the other lods to it.

My lods use the same texture (same file), but the lower lods use a different space on the uv map. As I tested in game, even on lowest graphics you can't see if the shirt has thickness or not, so I left lods unchanged from the base game shirt uv map and in the right position (on the same spot as all Sims 3 shirts textures are, but only mapped that way so you can't see it under the first lod's mesh). See screenshot.

Will it work this way or do I need to map all lods in the same spot (I mean normal map)?

All 3 lods use the same texture files(including the normalmap) so you are forced to build your lower detail meshes the same way.
If this is only for yourself(without uploading) you could considder loading the high detail meshes in the lower lods.

Have you seen the meshes i uploaded in the WRK file?
I remapped al the parts for you, but you are not going to use them?

Yes, I've seen them and I will totally use them. I just asked this, because I was curious how it will work on the lower lods.