Programatically collapse a panel

With Beta 2, does anyone know how to programatically collapse a panel controlled by the CollapsiblePanel extender? When I click a button, I want to collapse a panel and change the ImageControl(image) to a different image...Here's another thread that addresses the same issue and has a code sample, although I don't know if it's right since it doesn't actually work for me.

http://forums.asp.net/thread/1457087.aspx

I think this iswork item 5688.

this works for me

Me.CollapsiblePanelExtender1.ExpandControlID = "Panel3"

Me.CollapsiblePanelExtender1.Collapsed = False