Dependent controls in datalist add.attribute

 I have a datalist with two dropdownlist controls Adropdown and Bdropdown.
During edit I would like to have selectedIndexChange on control Adropdown autopostback and change the list options on control Bdropdown when user changes selection on Adropdown.
Selections are currently stored server side and really need to stay there. 
Remember: These controls only exist while datalist is in edit mode so I cannot just refer to the names of the controls in the code behind.
Within the Datalist editItemTemplate
<asp:DropDownList ID="Adropdown" selectedvalue='<%# DataBinder.Eval(Container.DataItem, "aFromDs") %>' selectedIndexChange='<%# getBdropdownItems(DataBinder.Eval(Container.DataItem, "minJobQualifications")) %>' runat="server">

<asp:DropDownList ID="Bdropdown" selectedvalue='<%# DataBinder.Eval(Container.DataItem, "bFromDs") %&g ...