how do I - dual movie layers

[snaprider]

Here's the problem... I have one movie which is my logo with an animated ripple effect {www.snaprider.com/Flash/logo (http://www.snaprider.com/Flash/logo).[swf and fla]} at about 50% alpha. I also want to have another wave animation {www.snaprider.com/Flash/underwater (http://www.snaprider.com/Flash/underwater).[swf and fla]} which has the effect of sunlight comming down through the water. My hope is to incorporate these two movies in such a way as to give the rippling/shimmerring effect of my logo being suspended underwater, and yet having the sunlight hitting it.
Both these animations were created by other parties, and have been only slightly modified by me.
My other delima is that on the "underwater" logo all 90 frames are the wrong demension... I want 800X300. Is there a way to readjust the size of all of the symbols all at once, vs. having to do them one at a time? {this question is more or less mute...until I can figure out the first one}

Any assistance would be appreciated. I know it is possible to "embed a movie instance" that loops inside one keyframe of another movie and have it run a continuous loop (as this has been done on the template I received for my actual web page www.snaprider.com (http://www.snaprider.com/)), however I don't know how this was done. Again, any thoughts are very welcomed.

[Scottae]

Check out this thread on editing multiple frames

[snaprider]

Check out this thread on editing multiple frames
Thanks... I will try that. In the interim I also stumbled accross another issue, that I have been working diligently trying to resolve, but as yet have not found a solution to. My "logo" animation is 12 frames long with a fps time of 12fps, however, the "underwater" animation is 90 frames long at 30fps. I guess I am finding afterall, that my question of embedding a movie into a layer is a relevant one. I know in theory, what I would like to do is put the "underwater" movie on one layer {properly scaled as per the technique offered in your response} and then place the "logo" movie on another layer. Then, stretch the two layers to be equal-distant (the same length), so that they both repeat their individual loops in synchronization (I hope that makes sense). My thought is that I may need to draw out my "logo" animation to 36 frames (thus making a larger file - not really desired) so that it is 3 seconds long, just as the "underwater" movie is. To be honest I am at a complete loss here... any recomendations will be greatly appreciated. I appologize in advance for my noviceness.
{quick thought:: is there something that can be done envolving utilizing the javascripting? I'll be honest I have no experience with this, but have found that it is usually what you know the least about and dread having to plunder through learning that usually presents the greatest amount of success when facing a challenging situation}