Seems to be flaw in setOrientation() to me. Right now, i'm highly confused about all the coordinate system and space conversions taking place, but...actually i would expect this to be a null operation:
camera.setOrientation( new SimpleVector( 0, 0, 1 ), new SimpleVector( 0, -1, 0 ));
...but the actual null operation is
camera.setOrientation( new SimpleVector( 0, 0, 1 ), new SimpleVector( 0, 1, 0 ).normalize() );
which is correct when viewed from the rotation matrix' point of view but it's not what you would expect given jPCT's coordinate system.
Also, getUpVector() should return the same value that you've given the setOrientation()-method, but actually it doesn't. I'll fix this. For now, simply doing a skalarMul with -1 with the up vector should do the trick.