Three Austrian teenagers were sentenced Wednesday to up to six months in prison for attacking Holocaust survivors and shouting Nazi slogans at a former concentration camp last year .A court in Wels, in northern Austria, found the three guilty under a law banning Holocaust denial, after they attacked visitors during a commemoration ceremony at the former Nazi camp of Ebensee on May 9, 2009.The teenagers, none of whom were previously known to police, fired compressed air rifles, injuring two visitors, made Nazi-style salutes and shouted slogans like “Heil Hitler” and “Sieg Heil,” according to witnesses.I ncriminating music and pictures were also later found among the boys’ possessions.This was “no youthful prank,” the prosecutor argued.The incident had sent shockwaves through Austrian society, prompting fears of a rise in neo-Nazi activity