Cannot redownload and install Borderlands

[patientzero]

Hello,

I purchased the game Borderlands from the mac app store and had downloaded it and installed it initially fine and well.

I made the move to Lion from SL and decided to do a clean install on a new drive.

I want to reinstall the game but the game says it's already installed and the hold-option-click thing doesnt allow me to install the game.

Thanks for time and consderation!

J