Tutorial for getting rid of DS Transitions in KOTOR II: TSL.
Original Thread (http://www.lucasforums.com/showthread.php?s=&threadid=146243)

You will need Fred Tetra's KOTOR Tool. Available Here! :D (http://kotortool.home.comcast.net/index.html)

I'm also going to assume you know the basics of the KT program, now on to the instructions.

The First step is to, open up heads.2da with KT, if you have one from a mod in your override then open this one, otherwise open one from the game files (BIF's/2DA)... you will want to edit all the following cells to "****", without quotes;

headtexvve
headtexvve
headtexe

The only rows you don't edit are the following; (Unless you want to remove the NPC's DS Transitions as well)
-------------------------------------
96 Atton
98 Visas
99 Handmaiden (#1)
100 Bao-Dur
117 Mira
128 Deciple
143 Colonel Tobin (Being Tobin is a dedicated NPC, you should probably leave this one alone)
171 Handmaiden (#2)

Once you have changed all the proper PC's/NPC's cells to "****", without quotes. click on another row you didn't edit, row 0 or 1 are good choices, then save the heads.2da to your override directory.

The second step is to open up appearance.2da with KT, if you have one from a mod in your override then open this one, otherwise open one from the game files (BIF's/2DA)... the player character rows are 91-180, 543-548, 578-580, and 663-668. on these player rows you will want to change the following cells to "****", without quotes;

texaevil (This is the DS Underwear)
texlevil (This is for female PC's only and is the DS Dancer Outfit Texture, this will allready be **** for the Male PC's)

You can also do this same thing for your party NPC's as well.

Their lines are the following;
------------------------------------
451 Bao-Dur
452 Atton
454 Handmaiden
455 Krea
456 Mira
457 Visas
561 Deciple
462 Mandalore

Once you have changed all the proper cells to "****", without quotes. click on another row you didn't edit, row 0 or 1 are good choices, then save the appearance.2da to your override directory.

The third step is to open up portraits.2dawith KT, if you have one from a mod in your override then open this one, otherwise open one from the game files (BIF's/2DA)... This will rid you of the DS transitional character portraits. You will want to change the following cells to "****", without quotes;

baseresrefe
baseresrefve
baseresrefvve
baseresrefvvve

Once you have changed all the proper cells to "****", without quotes. click on another row you didn't edit, row 0 is a good choice, then save the portraits.2da to your override directory.

Now you are done, if all went well, load the game and open up your previously undead-looking Sith PC and revel in your newfound lack of corruption/undeath! We are Sith after all! Not Vampires or Ghouls! ;)

I hope this helps! :D

Update: (KotOR I Addendum)

Thank you very much, that looks do-able. However, I was hoping to make the change with KotOR 1, not 2. Will it work the same?
It should indeed work the same...

Just in heads.2da you need to edit lines 26-55 as indicated in the Tutorial. In portraits.2da you need to edit lines 1-12 and 15-32 as indicated in the Tutorial. ;)

Also you won't have as many entries in appearance.2da to edit to get rid of the DS undies... you will only have to edit rows 91-180 as those are the player rows in KotOR I, again as indicated in the Tutorial.

Note for appearance.2da you will not have to edit the texlevil cell as it doesn't exist in KotOR, this only exists in TSL. ;)