Topic: Pre-download and not enough space.

I can't fully download the game using the pre-downloader because it claims that I don't have enough space on my hard drive. This is due to my hard drive being partitioned and the default downloading path being set to the drive that I keep all of my system files on, which happens to be small enough to contain just the system files and a little more.

Does anybody know how I can change the location where these files are downloaded so I can download it to a larger partition? I know it's possible as there was a forum post here on the WoW forums describing how to do it a couple years back, but I've since forgotten how and have lost the post.