Exception message thrown from C++/CX async method consumed in C# app

I am writing C++/CX WinRT library targeting Windows 8.1 which I want to consume from C# app.
If I throw exception from asynchronous method, exception message shown in C# app is wrong.

In WinRT library I have C++/CX code like:

IAsyncOperation<int>^ test()
{
    return create_async([]() -> int
    {
        throw ref new Platform::Exception(E_POINTER, "My message.");
    });
}

In C# app I have code like:

try
{
    await c.test();
}
catch (Exception ex)
{
    Debug.WriteLine("Exception message: {0}", ex.Message);
}

Output in debug mode is:

    WinRT information: My message.
    First-chance exception at 0x77692C1A in App1.exe: Microsoft C++ exception: Platform::Exception ^ at memory location 0x09A5E434. HRESULT:0x80004003 Invalid pointer
    WinRT information: My message.
    A first chance exception of type 'System.NullReferenceException' occurred in mscorlib.dll
    Exception message: Object reference not set to an instance of an object.

I know about this problem. However, that is solved for Windows 8.1 apps. I succeeded to pass my exception message from non-asynchronous method, but I can't get it working for asynchronous. Can anyone help me out with this?

If it is asynchronous, it means the function c.test() is executed in another thread, the thread can only catch the exception form its own, so you code won't work.

Instead using exception, you can use return code. Also in this MSDN article: Best Practices in Asynchronous Programming, the first thing it talks about is: Avoid Async Void.