Why isn't IID_ITaskbarList3 defined?

[Nieto]

I'm trying to write a blinding and I found both IID_ITaskbarList 
and IID_ITaskbarList2 are defined but IID_ITaskbarList3 isn't. 
Any reason why it isn't defined? sorry if it sounds such a naive 
question, I'm new to COM and D interop. I knew a thing or two 
about PInvokes with C#.

Then how do I define it myself?

I've tried this:

> GUID IID_ITaskbarList3 = 
> createGUIDFromString("{ea1afb91-9e28-4b86-90e9-9e9f8a5eefaf}");

> GUID createGUIDFromString(string guidStr) {
>		GUID guid;
>		wchar* GUID_STR = toUTFz!(wchar*)(guidStr);
>		HRESULT hr = IIDFromString(GUID_STR, &guid);
>		assert(SUCCEEDED(hr));
>		return guid;
>	}

I'm unsure if it's the proper way to do it (if not, please show 
me the right one)

But the call to CoCreateInstance() still fails to access any 
member of m_pITaskBarList3 object, so I'm making sure I'm passing 
the correct arguments to the function. The memory access error is:

> object.Error@(0): Access Violation



> HRESULT hr = CoCreateInstance(&CLSID_TaskbarList, null, 
> CLSCTX_INPROC_SERVER, &IID_ITaskbarList3,
> cast(void **)   &m_pITaskBarList3);
> assert(hr == S_OK);

The assert() doesn't run, so the error is somewhere else... I 
guess.