This works in IE9, I doubt it will work in IE8, but it's worth a shot:
_IEFormElementSetValue($element, $oItem.value)
Local $oEvt = $oIE.document.createEvent("HTMLEvents")
$oEvt.initEvent("change", True, False)
$element.dispatchEvent($oEvt)
If it's not working for you, you might try this:
_IEAction($element, 'focus');focusing helps sometimes with java functions
_IEFormElementSetValue($element, $oItem.value)