Adding ajax:RoundedCornersExtender Dynamically

I have a page where I have a Accordion panel but adding the panes dynamically:

 pn = new AjaxControlToolkit.AccordionPane();
 pn.ID = "Pane" +  dr["PostingID"].ToString();

I'd like to be able to round the corners of these panes. The issue is that the ajax:RoundedCornersExtender requires a TargetControlID which is created at runtime (see above). The above snippet is part of a loop, so there are many panes created.

Is there a way to round the corners of the panes? Is there a way to add the ajax:RoundedCornersExtender dynamically and set the TargetControlID dynamically as well?