Why doesn't my iTunes software save the downloaded tracks from buffered previews on the iTunes Store? It is a waste of bandwidth when iTunes deletes the preview if I start previewing another item, and then want to go back to preview the first item, only to need to download the whole file again. The video previews each take several minutes to download on a high-speed connection. iTunes should store the previews at least until the end of the session. Is there an option for this somewhere in the software that I'm missing?