Get one off a 2006 as it has rounded corners. I am not usre if it will fit though. You might want to go to a dealer and see if it will match up. You may have to buy the whole batery box & cover to get it to work.

 

Relocate the battery.
Put it in front behind a chin spoiler.
Then cut down the battery cover to make it narrower in the frame.

 

The chrome one has rounded edges

 

Wescoot2'slink is the one I was talking about- same part #. The '06-newer ones don't fit, but I guess you can make anything work if you really want to...