Animated GIF preloader

Hello,

Not sure if this is possible but I am trying to create a preloader for use on a website which has a lot of high quality image and graphic content.

What I want to do in either WD7 or Designer pro 6 is merge an animated gif that I have downloaded from the web with a transparent copy of the home page and then save that as a gif animation to use as the preloader (with some code I have downloaded from the web). I can get the small animated preloader to work on its own ok but when I create a new new gif file, add the animated gif and the background layer and use this it is just static - the animated part doesn't work. The reason I am trying to do it this way is because using just the small preloader while the page background elements are loading looks messy.

Thanks for any tips!

Andrew