for some reason the klinks dont want to get tractored in that mission, and will break your first attempt, I have been able to lock on to them a second time and it didnt immediately break, but they were already too far gone by the time i got going in a direction that wouldnt take them into the singularity. So i too have yet to win at that mission myself, maybe if i were a bit faster, or stop myself near the ship and wait for him to break a level 1 beam, then snag him with a level 2 or 3.