When you do enough quests on Nar Shadaa you will get a cutscene of Trandoshan slavers taking over the Ebon Hawk. Go deal with them and the next time you set foot on Nar Shadaa you will get a cutscene arranging a meeting with one of the Exchange bosses there. On your way there you will be intercepted by another character. If you are dark side at this point you will eventually play as Hanharr after which you will be able to recruit him.