Hi Ian,
Sorry to have tell you this, but I had to revert back to the older version of AjaxControl toolkit because the new version created a bug in my Form Wizard Pro product due to a bug in the ReorderList control in the newer versions of AjaxControlToolkit. I found it is a known bug but it is not fixed.
http://www.codeplex.com/AjaxControlToolkit/WorkItem/View.aspx?WorkItemId=17574
I will have to revisit this later.
Best,
Joe