Working with COM objects isnt obvious! =(

[Divergence]

Hi! Sry for bad english, first of all =)
Only today i learned something about COM inteface. It is very hard to understand for me, how to use this tool. But i trying to understand =)
I need help from skilled guys, coz my effort gone to noway!

Here is a typical example of my pains:
We have class ID2D1Bitmap that inherited from another class, that i dont need. I need only ID2D1Bitmap class (it is COM class). And i wanted to create one. Simple, realy? =)
All that i can do is:
ID2D1Bitmap *pointerBitmap;
But this is Acces Violation. I need to allocate memory for it.
The only function for creating instances of COM objects i know is

HRESULT CoCreateInstance(
  _In_   REFCLSID rclsid,
  _In_   LPUNKNOWN pUnkOuter,
  _In_   DWORD dwClsContext,
  _In_   REFIID riid,
  _Out_  LPVOID *ppv
);

But my problem, is that i cant find CLSID for ID2D1Bitmap! And dont know another parametrs! So, i think: maybe another function will be more usefull? But i cudnt find it!
Guys, plz help me!
Tell me how and where i can find information, about creating new instance of COM-class! I cant find it in MSDN or i dont know WHAT to find and HOW to find it.
Any adwices will be very nice!

[Divergence]

This object creating with inner function. My problem were wrong convertation formats.