Yeah @Playinagame is right. All my miles are with Virgin Australia, but you would be able to fly from America with Delta and do all your internals on Virgin Australia. However, from Europe, not really unfortunately.
(I did the Virgin/Delta combo recently and it was excellent to be honest.)
Yeah, the thing is I’m European, and even if I’m working in America now, it’s more easy i would start from Milan (I’m Italian). And I’m taking the miles with KLM/AirFrance (Flying Blue)… So it’s not that easy, I know there is Korean Air though, I may can use that one, but I’m not sure on an awarded trip.