To do this, you'll have to board their capital ship in the area. In order to stymie the Rebel attack, you're going to have to disable the Rebels' most powerful asset - their ion cannons. You'll have to fly through part of the shipyard for this - don't be afraid to go slow, you'll have plenty of time to get those Rebels off his tail.
After confirmation of the Rebel shuttles being destroyed, you'll have to regroup with Hask, who's being pursued aggressively by some Rebel fighters.
