hello....

i was doing a simple motion tween animation (clouds moving across a sky) and some of them overlap over the 'edge' of the document so only part of the cloud is showing (like i want) but after i publish or export the file into swf for some reason there is a white line/edge at the top where the extra part of the clouds is showing and i dont want it to How do i fix this so the swf file doesnt show the part that is supposed to be hidden?? i thought it would publish what my document size is (1224 X 560 pixels) but its showing that extra and im sooooo FRUSTRATED.