~/Library/Application Support/AppStore/ Missing!

The title says all.

I tried to download several programs on the mac app store, including mountain lion.

But when ever I paused the download and continued the download, the whole process started from the beginning

So I wondered where the app store stores the downloading files...

After googling for a short time, I found out that it store the content under the ~/Library/Application Support/AppStore/ folder.

But the problem is I don't have this folder in my Application Support.

Does anyone have the same problem here? How can I solve this ?

Thanks for the information in advance.