Customising Horizontal scroll bar using MFC

Question

I m trying to customise the Horizontal scrollbar for a view in MFC edit control. and trying to set ScrollInfo to the same.

SCROLLINFO ScrollInfo;
   ScrollInfo.cbSize = sizeof(SCROLLINFO);
   ScrollInfo.fMask = SIF_PAGE | SIF_RANGE;
   ScrollInfo.nMin = 1;
   ScrollInfo.nMax = INT_MAX;
SetScrollInfo(SB_HORZ, &ScrollInfo, TRUE);

But the scrollbar is not setting up to the actual width of page.

Am I missing something.? I have attached the image also that shows the difference between the standard horizontal scrollbar and the customised horizontal scrollbar.