Realtime Obj Importer Build to windows app store issue

i think the problem is comming from the script it self , because when i build it to wpf it works fine ..
inside the script i uses : 

public string url = "file:///D:/1.jpg";

IEnumerator Start()
{
WWW www = new WWW(url);
yield return www;
renderer.material.mainTexture = www.texture;
}

i think that the protocol FILE:/// does'nt work in WINRT ..
so what's the equivalence of it ?