Thanks guys, for your response. I have found the solution already however, I had to enable the little asterix next to the layer, so the transformations are collapsed in the pre-comp.
About making copies of all the layers; that’s a good route that I usually take when dealing with this kind of problem, however, this time I choose the 3d route because I have 20 pictures that have to slide over and under each other all the time, and each time in a different order. So I would have been forced to make about 10-20 copies of every picture to make this work. Not very attractive. With lesser picture or layer order-transitions this would have been the best route however. Thanks anyway!
Steven