Forcing Scrollbar at bottom

I'm using a VScroll control. The view window shows 4 cells (UCs) in a column. Each cell is 128 pixels high.

When the view window has a max of 4 then the scrollbar is fully expanded. As I add new cells the scrollbar progressively gets smaller in height and stays at the top. I want the scrollbar to move down so that the last cell added is always visible at the bottom of the view window. How to do this

I tried this

SendMessage VScroll1.hwnd, EM_SCROLL, SB_BOTTOM, 0


but it doesn't work