Making Coat/Jacket Addons

[DuxSupremus]

I've got a fairly simple mod in mind, but I have difficulties getting it beyond NifSkope. I'm trying to edit some outfits (ex: Colonel Autumn's Uniform, Junior Officer Outfit, Vault Lab Uniform, Tunnel Snake Outfit, &c) to have just the coats, to use as BodyAddOns over other outfits. Think like Tailor Maid. Getting them free of the rest of the upperbody and fitting them over a variety of outfits takes some cutting and resizing, but I can do that fine (I'm using 3DSMax):

 

http://xs743.xs.to/xs743/09396/examplecoats939.jpg.xs.jpg

 

The trouble is getting them sorted and put into the game. Going back into copies of the Original outfits and pasting the Edited data (NiTriShapeData, NiSkinData, NiSkinPartition) over existing entries (as per Skree's guide) results in giant messes of polygons. It's pretty clear the dismemberment and skin data gets pretty messed up in the chopping-down process.

 

Considering the models come from Fallout 3 and thus have weighting available, it doesn't make sense that I would have to skin them all over again from scratch, and apparently this source agrees, but whenever I try and copy skin data from the Original to the Edited model, I get weird displacement problems (for Junior Officer's Outfit anyway):

 

http://xs843.xs.to/xs843/09396/dispweirdness860.jpg.xs.jpg

 

Manually moving it backwards doesn't last--it always reverts to the same position. Dismemberment data copied from the Original to the Edited model remains messed up and in exactly the same fashion as what the Edited originally displayed after editing, but I'm not too concerned about that as the outfits below will have dismemember data. Colonel Autumn's Outfit doesn't have displacement issues, but still has obvious problems:

 

http://xs743.xs.to/xs743/09396/almostnotquite275.jpg.xs.jpg

 

I know that this can work, I just can't figure out this intermittent step. I'm guessing that I'll have to manually repaint either skin or dismemberment data or both, but if anyone could offer advice or point out what I'm doing wrong, I'd appreciate it. Thanks.