Hi Sky,
Thanks for your reply! I actually found a solution and the cause why there is a huge shadow. When you add a png to a plane you must check whether the plane has a back material. If so, that's the one that casts a shadow. When you remove the back material all is fine ;). But thanks again. Oh and please add the round edges option like Lumion and D5! :)) Have a great day and keep up the good work!