if you link your movieClip in flash ide for swc export into FD like this : (for instance) folder1.folder2.class ... and the baseclass is movieclip, then in FD, you can't access the properties of that movieclip, nore the movieclips and assets inside it.
but if you link it like this myClass and the baseclass folder1.folder2.class, it works, (so myClass extends folder1.folder2.class).:) i posted a thread but nobody answered :(
