Ajax AutoComplete Extender in IE9

Hi! I am trying to make my application compatible with the latest versions of browsers, but I am facing a weird issue in what concerns the ajax autocomplete functionality. It works fine in regular pages (when the page is not constained inside an iframe), but when it comes to using it for a textbox inside an iframe, its display position is beyond my expectations. No matter for how many textboxes I am using the autocompleteextender, the completion list seems to display for them all at the same x-y coordinates.
I am using AjaxControlToolkit version 1.0.20229.20821. Could this be a problem with the control or with IE9?
Thanks!