In Windows Vista and Windows 7, ToolTips have a new visual style or theme, they are shiny grey metallic. How can I enable the new style for a ToolTip control?

Some controls, like ListViews and ToolBars, use the new tooltips automatically, but other tooltips are rendered with the old yellow XP style.

I've tried sending an TTM_SETWINDOWTHEME message but nothing happens and I'm not sure what string I am supposed to use for the visual style name.

SetWindowTheme doesn't work either, I've used it successfully on ListViews and TreeViews to set the "Explorer" style (see http://www.danielmoth.com/Blog/TreeViewVista.aspx), but that doesn't seem to work on ToolTips.

I'm using the plain win32 C API.