如何在RadGrid的FormTemplate中设置Telerik RadComboBox的SelectedValue属性

I have what I think should be a straightforward question. I have a RadGrid with FormTemplate editing and AJAX enabled. One of the fields in the FormTemplate is a RadComboBox filled with U.S. State selections. I can bind the RadComboBox to the data source to populate all the items, but I'm not able to set the SelectedValue attribute.I have what I think should be a straightforward