Here's what you can do to continue using the Class Wizard. At the top of your implementation file (cpp file) will the the message map which begins with a line like
BEGIN_MESSAGE_MAP(CMyListView, CListViewEx)Class Wizard uses the second argument in this macro to decide whether it needs to display more messages. Since class wizard doesn't recognize the CListViewEx class it does not show any of the list view control messages. What you can do is change the line to
#define CListView CListViewEx BEGIN_MESSAGE_MAP(CMyListView, CListView) #undef CListView
This will now allow you to add message handlers for the CListView class.
Thanks to Gert Rijs from Netherlands for suggesting the use of the #define directive. It fools the Class Wizard parser but provides the right code to the compiler.