Well, I'm just about the last guy to say that I'm a modeller, but I do know a few things about the game's models...
Some basic info about modelling/animations in KotOR 1 and 2:
A body/armor model in the KotOR games relies on an "invisible" set of "bones" for animations.
NWMax/KotOR relies on Key-Frame animation, where you make position and rotation keys for the various frames of an animation and these frames are transformed into Time-Key animations upon exporting the model.
The invisible set of bones is listed here in this picture:
If you aren't familiar with the term, "rigging" a model is where you give the model a bone structure that allows it to be animated in the way that the game uses animations.
So, to get your models into the game, you'll need to import these bones from one of the game's supermodels (S_Male01, S_Male02, S_Female01, S_Female02, and S_Female03).
However, your model itself will need to be divided up into the Left Arm, the Right Arm, and then the rest would be labelled "Torso". After that, you'll need to look at another armor model, since the Left Arm, Right Arm, and Torso all should be Editable Meshes with the Skin modifier on them.
The Skin modifier will need the bone structure from another model (AKA look at another model and link your bones together in the same hierarchy if they aren't already when you import them), which you can do by "Add" button on the Skin modifier by the Bones section.
After the bone structure is done, you'll need to "weight" the bones and vertices to have an appropriate force exerted on the pieces of the model when it's moved around (which will also affect how the texture is stretched when the model moves). This part I honestly can't help with, so I'd look up some tutorials online (not necessarily around the Star Wars areas of the net, but more in the Modelling Tool's forums).
Just remember that after you get the Skin modifier on onto the piece, DO NOT convert the Editable Mesh to anything else or the data for the Skin modifier and bones WILL be lost... There's nothing like having to redo the weighting...