The Korean side of GamePark's website has a full list of accessories, including:
GamePark Korean Battery Cover Page
But... I don't know if non-Koreans are allowed to buy from the Korean language part of the site.
(I can't read it!)
Can anyone shed some light on this?
I downloaded one yesterday and the only payment option listed was credit card, so I guess that's all they accept.
The Korean language section of the site looks like it may have that "mileage" stuff, but I can't read what any of it says.