I know Shakhtar pretty well, hence I think they will progress. But there are many factors you should consider: Salzburg plays its homegames on artificial turf, usually a big advantage. Trap is a shrewd tactician. And I mentioned only a few players, the team is even and has no weak players, but no stars like Castillo, Brandao or Lucarelli.
Salzburg is vulnerable in defence. Shakhtar should use it and score in Salzburg, that would seal 50% of the deal, cos they are really bad at away games.
And one fact: I am NO Salzburg fan. If Shakhtar makes it, I'd be glad to see it.