animated as in it changes position? with like a 2DPlacement node? Because in that case all what you have to do is conect the node governing the position of the file node that you are using as a texture to the file node with the transparency?
Ummm, I'm a little confused by what I just said... let me try again:
You have a file Texture.tif with an alpha channel. Open the file in photoshop and save two new files, one is the same image but with no alpha called TextureOnly.tif, and the other also doesn't have an alpha, but the image is what the alpha of the original file was, TextureTransparency.tif.
Then Create a file node fileTextureOnly and another fileTextureTransparency. Then asign a 2dPlacement node to fileTextureOnly and move it around in what ever way you wanted to animate it. Then, without deleting the conections between 2dPlacement and fileTextureOnly, asign 2dPlacement to fileTextureTransparency. That way all the movements of the texture will also happen for the transparency (I hope :p).
Now, maybe you are animating it in a different way :-/ but I think that's the only way that I know how to do it.
There can not be Good without Evil, so then it must be good to be Evil sometimes.