I would use clipping in your View3D, are you using that at all?
It would be something like this:
var W:Number = 1024;
var H:Number = 600;
_view.x = W/2;
_view.y = H/2;
_view.clipping = new RectangleClipping({minX:-W/2, maxX:W/2,
minY:-H/2, maxY:H/2});
Say _view is in a clip called "away3dHolder" which is at 0, 0.
When loader loads the swf, away3dHolder should be at 0, 0, and the view
centered with the correct clipping applied to it (there will be no rendering
outside of the clipping rect you specifyed).
Hope it helps!
Li
