Image Ready help

I'm trying to make a fairly simple fading animation with a bit of overlaid text. I put in the two images, did the Tween thing, added the text, blah, blah, blah. But here's the thing. No matter how I do it, the top image in the layers is always going to be dominant. What I'd like to do is fade from Image 1 to Image 2 with Image 1 on top. Then on the fade back, I'd like Image 2 to be on top. Is there any way at all to do that, cuz I couldn't figure it out.

I'm on a Mac running ImageReady 7.0, but if you give me directions in PC-eese, I'll most likely be able to translate on my own.

This is the icon as it stands now: