I was able to set the name attribute value to a radio button in IE8, but not in IE9. Firefox still does not offer ability to select radio input element so currently it is not possible to provide this feature in this browser.
I logged the IE9 problem and we will fix it. Here you can find the PITS Issue: Public URL
The temporary solution is to render the page with RadEditor in IE8 mode by putting the following meta tag:
http-equiv="X-UA-Compatible" content="IE=8" />
the Telerik team