How do you defeat ozzik stern in Star Wars the force unleashed

Here is how it works:Run at the AT-KT while using lightning,then attack the legs. Then a blue shield will go around him his AT-KT.It comes from these ball looking things, drestroy them. And his shield will go away,he will get more than one shield. Repeat this prosess until the AT-KT is destroyed.Then a cutseen will appear and you will kill Ozzik Sturn.