I believe thats how it normally works anyhow O.o
The exchange message should kick in after you've completed enough sidequests on Nar Shadaa, you don't need to kill the exchange boss, or the gang on the Ebon Hawk as far as I know. All you have to do is walk around and talk to as many people as possible, completing as many quests as you can.
However, as for the request you made, I woudn't know how to do this either, but it seems to me you would have to tamper with the global scripts or something. Can't help you anymore though, I know very little about the global scripts, or how to manipulate them.