captureScreen retina display

Is there any way to capture screen in retina display with 640x960 resolution? When I use captureScreen function in iPhone 4, I can only get a 1280x1920 image.

my config.lua file…

[code]

application =
{
content =
{
width = 320,
height = 480,
scale = “Letterbox”,
fps = 30,
antialias = true,
imageSuffix =
{
["@2x"] = 2,
},
},
}

[/code] [import]uid: 14440 topic_id: 9471 reply_id: 309471[/import]