How to use transparent png in createfrompng?

Hi! I'm having problems with createfrompng… I do the following: 1 Creates a new image 2 Fill it with black 3 copy an jpg on to it 4 write some text 5 tries to use copyimageresized to put a transparent png over the whole image… It's in point 5 it goes wrong, because of some reason the png loses its transparens and becomes a white square instead of the nice transparent picture it was from the beginning… What have I done wrong or is it simply impossible to perform what i want? Sincerely Victor