Let's say you download a recruitment mod (like this one (
http://knightsoftheoldrepublic.filefront.com/file/Recruitable_Kay;85258) for example) for a character that does not have an underwear texture/skin. You want to give this new character the main PC's scoundrel underwear texture/skin. How you go you go about doing that?
You'll need to change the appearance in the 'underwear' column to that of the scoundrel in appearance.2da. Just change the model and texture to those that appear for the scoundrel's underwear appearance.