Disabling File->open in main frame of an MDI

I have been trying to disable File->open in main frame of an MDI application that I made using the MSVS .NET wizard.
I tried EnableMenuItem(..) but I don't know how to get an HMENU for the menus created by the wizard. Any help would be highly appreciated.
Amish

Find the menu item in the 'resouce view'. Add an event handler that does not call the default handler for the item (remove the call and return true).

or

Look at the 'Resource View' window and find the main menu, set items property to disabled.

or

As above but find menu items ID (ID_FILE_OPEN = file open in IDR_MAINFRAME main MFC created menu)

then, with error checking added to code.

Code:

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//get the main window
CWnd* pMain = AfxGetMainWnd();
//find menu
CMenu* pMenu = pMain->GetMenu();
//you may have to get the sub menu here (not 100% sure)
CMenu* pSubMenu = pMenu->GetSubMenu(0); //left most sub menu
//disable item
pSubMenu->EnableMenuItem( ID_FILE_OPEN ,MF_BYCOMMAND|MF_GRAYED); //default MFC file open ID#

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