How to access IDispatch pointer for an activex control instead of using ctrl wrapper classes

Hello,

I want to access a custom activex control I created, lets call it MyControl through the IDispatch method.  Sometimes adding the wrapper class to the main app dialog does not show new put and set funcs which correspond to properties added to the control.

So in my dialog .cpp  file in the main app, which includes MyControl in the dialog.
1\  What do I have to include to access my activex control?  I have tried to include the ctrl class header file from my activex control project, that does not work.  Also, do I include the tlb file?

Then later in the file in func OnInitDialog()

CWnd* m_Wnd;
IUnknown* m_iUnknown;
CMyControlCtrl   m_activex;    \\class is my control class within my activex control

m_Wnd = GetDlgItem(IDC_MYCONTROLCTRL1);   \\get the control id for my activex control on the dialog

2\  What is the correct way to do the query inerface with the first input parameter? the func def takes, REFIID riid as the first parameter.

m_iUnknown->QueryInterface(????, (LPVOID*) &m_activex);

Once I have done the correct query I should be able to access the control through
m_activex->xxx

Thanks in Advance!