"He knows in his heart he is totally innocent of these charges and believes in the jury system," O.J. Simpson attorney Yale Galanter said yesterday upon learning his client would stand trial for the now-infamous shit-recovery armed ambush of two sports memorabilia dealers in a third-rate Las Vegas hotel room. And while we have no doubt Galanter is at this very moment frantically scribbling down and crossing out potential catchphrases on a legal pad ("If the gun don't load, it can't explode!"), Simpson is clinging to the sunny side of life, even chatting up his fellow Delta passengers on a recent flight of Las Vegas to Fort Lauderdale. Reports a Page Six source: