GameObject Monobehaviour.Texture -> Null

I have a gameobject in my scene with a script that contains objects called "Elements" these object contain various variables one of which is called "NormalTexture". I have assigned the texture by dropping it on the property in the editor but when running on windows phone the "NormalTexture" property evaluates to null.

public abstract class Element
{
[...]
public Texture2D NormalTexture, PressTexture;
}
public class ElementButton : Element { }

public class myGui : MonoBehaviour
{
ElementButton startButton, backButton;

void Start()
{
if (!startButton.NormalTexture)
Debug.Log("StartButton=Bad Texture");
}
}

//please note that startButton.NormalTexture is assigned in the Editor. By dropping a texture on it.
​

This only appears to be an issue on Win Phone 8. Any suggestion are greatly appreciated.

 

I am sorry for not being more clear.

I have tested this on Android and iOS builds. It also works as expected in the Editor.