Flash 8: Random start with control

I have a simple movie were I load one picture after the other with an alpha motion tween in between. I load the external pictures into a movieclip. I want to use this to promote six differemt blogs on my site. But it doesn’t look so dynamic as it always start with the same picture, I have tried an Action script to start the movie on a totally radom keyframe. And it works but often leaves the movie white for a while in the beginning since it starts without loading a picture if it doesn’t starts on a keyframe with the loading ActionScript.

So - to get to the point… How can i get my movie to start radomly on keyframe 1 or 100 or 200 or 300…?