Please find below a copy of my Watchlist. I am using Win 8 Release Preview, VS 2012 Express. If retrieved via getElementsByClassName().wincontrol, the tooltip object is found but if retrieved by getElementById().wincontrol, it fails. Please help.
container.getElementsByClassName('tooltip')[0].id
"aZ0_0Tooltip"
+container.getElementsByClassName('tooltip')[0].winControl {...} Object, (Tooltip_ctor)
document.getElementById("aZ0_0Tooltip").winControl
undefined