Sorry mate, it's bugged. It always uses the Exile's repair skill no matter who uses the workbench.
The only exception is when you have Mira, party of 1 at a certain point in the story. She gains access to a workbench. You can have her break down dozens of items at that point and have enough components to assemble lots of end-game items later.
Note the return on components you get from breaking down items caps at Repair skill 20.
I'm not sure if http://knightsoftheoldrepublic.filefront.com/ is kotorfiles, but searching there I found no such fix. Just a few mods to add more items you can make at the workbench (armor, lightsabers, etc.).
I do consider this to be a bug, given that you can use party members to craft items and it does use their skill level, not the Exile's. It sucks because you have to blow a feat and take Repair as a class skill usually. Only one starting class gets it naturally; I forget which one. Sentinel?
