Я уже это подозревал, но вот тут наткнулся на прямой ответ одного из сотрудников МС.

Он отвечал на вопрос есть ли в Лонгхоне новый анменеджед АПИ?

Вот его ответ:

WinFX is not a managed wrapper around new Win32 native APIs; it's a new
managed API, implemented primarily in managed code. The only way to access
the new WinFX features is through this managed API.

vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

There are no
corresponding native APIs.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

If you are starting a new project, we recommend
that you write it in managed code, which will provide maximum benefit,
particularly around the areas of security and reliability. However, if you
have existing native code and you'd like to take advantage of WinFX without
rewriting your app then you can use a language interop mechanism such as
that provided by Managed C++ to call WinFX from native code.

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Leonardo Blanco
Windows Client Platform Group, Microsoft Corporation

This posting is provided "AS IS" with no warranties, and confers no rights.