You need to include the WS_EX_CLIENTEDGE
extended window style.
You say that you have already tried including WS_EX_CLIENTEDGE
without success. I'm going to take a wild guess that you have been trying to include it in the window style rather than the extended window style. Your code should look like this:
hWnd = CreateWindowExW(
WS_EX_CLIENTEDGE, // extended styles
L"EDIT",
...
);