How to set kResolutionExactFit in Windows Phone 8 games using the Cocos2d-x wp8 v2.0 preview

cocos2d-x C++
#1

I begin to port my games to wp8 platform. I use in my games the following code

CCEGLView::sharedOpenGLView()->setDesignResolutionSize(480, 320, kResolutionExactFit);

I use this code to stretch images to all devices screens(this works with all android and ios devices) , but I can’t make this work on wp8 2.0 preview, there’s any other way to make this work?