Remember, he's already plead guilty and fled the jurisdiction of the tribunal before he was sentenced. There's no reason that the victim would have to testify - hence the purpose of the plea in the first place.
Also, he's looking at a felonious failure to appear from 1977 - the statute of limitation has not run out on that charge and it doesn't require the victim to testify. Long story short, he's going to see some real jail-time if he's returned to the US. And yes, I know about the case's problems and I say to them, "don't believe everything you see on HBO."
You've obviously never heard of Judge Ito...or the OJ jury.