Its fairly easy to get pirates to RP. Just find the right kind of insult, completely IC but without too much of wizard's robe added, and you'll have them going along in no time. They'll occasionally fall out of character, but the need to defend their ego's in front of their mates will have them directly respond to you IC challenge.
I usually phrase my insult as a question, which helps too.
"Mr. X, did you leave behind this pitiful wreck of that Matari rustbucket called a Rifter? It seem you left behind some fusion ammo, do you want it returned?"
"Incidentally, why did you call it 'pwnmobile'? Is this because you have a tendency to be 'pwnd' alot or do you have a thing for named target painters?"
There are few pirates who can resist such simple questions. When they respond, I simply continue phrase other questions or remarks based on their responses. Just feed their ego a bit at times and alternate with a couple of colorful insults, and you'll have an instant mini-RP conversation over local comms.
"Really, you are the Lord of this system? I wasn't notified. Is leaving behind a Rifter wreck like some kind of urine marker, like an animal that leaves droppings to demarcate the edges of his territory? And if you are the Lord, what kind of rules do you have here that I should be aware of?"
etc.etc.