well i know 2 way to have 3d motion in flash.
one is : swift3d v4 or v4.5, easy program, after u create 3d animation , go flash, import scene, and u will se a swift import format, so u can import swift 3d in flash scene.
second way: go to after effects, and do animation, after that xport like swf or import to flash this video and then convert to swf.