I’m not sure what difference it would make who actually fired the missile that brought down the aircraft. I don’t know anyone who believes that this incident involved the deliberate downing of a civilian aircraft (every indication is that the culprits thought they were shooting at a military jet) ... which means the Ukrainians/Russians will simply join a growing list of military forces — including the United States — who have done this sort of thing.
Considering the Russkies are claiming that the civilians were "already dead" for at least 2 days before they were put on the plane and flown over Donetsk and into the innocent missile minding its own busines (such is Strelkov's opinion), I do not think this will go over so nicely. Furthermore, we were sued in international court and paid a great deal in damages to the people in that down jet. It's not like nothing happened, and no nothing will be happening here.