Assign Nothing To The Structure And Not To Its Members

I'm having some headaches using Structures and functions that return Nothing in VB.NET. [Code] In the previous code, when I return Nothing as result of Foo function I'd expect that st is Nothing. But this is not what happens. Then I found in MSDN documentation: Assigning Nothing to a variable sets it to the default value for its declared type. If that type contains variable members, they are all set to their default values.

So I discovered that when I assign Nothing to a structure, all its members are set to their default values, instead of the structure itself.

Also, I tried to make st a Nullable type by declaring: Dim st As Nullable(Of Test) = Foo()

but, still I can't check if st is Nothing by using: If st Is Nothing Then

or If st.Equals(Nothing) Then

So, questions:

1 - Is it possible to assign Nothing to the structure and not to its members?
2 - How can I check if a return structure value is Nothing?