D.M.
Sorry for the late response to this, but I think you may have confused "Serbs", with "Ukranians", in your late-night-TV documentary viewing. There were NO Serbs among the many nationalities who faught in the Waffen SS.
http://en.wikipedia.org/wiki/Waffen-SS
But there were quite a few Ukranians serving as camp guards. Most notable among them, a former American Steelworker, John Demjanjuk, whom Justice Dept. investigators identified as a former camp guard named "Ivan the Terrible". His trials -- in the U.S., and in Israel -- took over a decade, I think, and were sometimes front page stuff.
But he, like the other guys, were all Ukranians, not Serbs