XML.load on WP8

Hi,

I'm trying to deploy my game on WP8, but I've a problem with my XML.load.

I use this:

#if NETFX_CORE && !UNITY_EDITOR
using XmlDocument = WinRTLegacy.Xml.XmlDocument;
#else
using XmlDocument = System.Xml.XmlDocument;
#endif

And my VB application crashes when execute this: (it works fine on IOS or Unity Editor):

xmlDoc.Load(new StringReader(textAsset.text));


It's said me that I had a unhandled exception 'System.NullReferenceException' in WinRTLegacy.DLL.

Any idea to solve this problem ?

Thanks a lot.