TextAsset not found in AssetBundleLoadAssetOperation

Hi,

I can't get the TextAsset with this code on Unity 5.4.0f3-Windows10:

Code (CSharp):

1.  AssetBundleLoadAssetOperation msg = AssetBundleManager.LoadAssetAsync(assetBundleName, "ClassLibrary1.bytes", typeof(TextAsset));
2.  
3.         if (msg == null)
4.         {
5.             print("no");
6.             yield break;
7.         } else {
8.            print("yes");
9.            }
10.         yield return StartCoroutine(msg);
11.  
12.  
13.         TextAsset txt = msg.GetAsset<TextAsset>();
14.         // Load the assembly and get a type (class) from it
15.         print(txt);
16.         var assembly = System.Reflection.Assembly.Load(txt.bytes);

yes is printed but print(txt) throws null then of course I don't get assembly:
Object reference not set to an instance of an object
LoadAssets+<InstantiateGameObjectAsync>c__Iterator3.MoveNext ()

I double checked the Asset manifest and ClassLibrary1.bytes is present (hence the "yes" print).
And it's compiled with .Net 3.5.
Any idea?
Thanks