Thank you for your reply.
I was able to get the Native Element of the Rad Control through IHTMLElement2 (as described here: http://social.msdn.microsoft.com/Forums/en-US/vsautotest/thread/c38306bd-b45f-4ae2-bbf2-b81ff427f8ba
But I wasn't able to figure out how to access it's methods or properties.
"var obj = window.$find('" + id + "');obj.showDropDown();
obj.findItemByText('" + item + "').select();