How to register PostBackTriggers in a GridView nested within an UpdatePanel?

I have the following UpdatePanel code:

<asp:UpdatePanel ID="MyUpdatePanel" runat="server" UpdateMode="Conditional"><ContentTemplate><asp:PlaceHolder ID = "MyPlaceHolder" runat = "server"><asp:GridView runat = "server" ID = "MyGridView" DataKeyNames = "ID, Name" AutoGenerateColumns = "false" ShowHeader = "true" GridLines = "None" OnRowDeleting = "Delete" OnRowEditing = "Rename"><Columns><asp:TemplateField><ItemTemplate><asp:ImageButton ID = "RenameButton" Width="15" Height="15" rel="tooltip" data-toggle="tooltip" title="Rename" runat = "server" OnClick = "Rename"/><asp:ImageButton ID = "ExportButton" Width="15" Height="15" rel="tooltip" data-toggle="tooltip" title="Export" runat = "server" OnClick = "Export"/><asp:ImageButton ID = "DeleteButton" Width="15" Height="15" rel="tooltip" data-toggle="tooltip" title="Delete" runat = "server" OnClick = "Delete" />                       </ItemTemplate></asp:TemplateField></Columns></asp:GridView></asp:PlaceHolder></ContentTemplate><Triggers><asp:PostBackTrigger ControlID = "MyUpdatePanel$ctl02$ExportButton" /></Triggers></asp:UpdatePanel>

What is the proper way to register ExportButton in a fully scalable manner? The code as shown works only when there is 1 row in the Gridview - if the GridView is empty it causes a server error and if there is more than 1 row, only the first ExportButton is registered.