LinkButton has default theme defined - although different skindIDs are given

Question

Hi, I have a datagrid and an itemtemplate in it. I want to assign a skindID to the item template, but I get the following error:

Type System.Web.UI.WebControls.LinkButton already has a default theme defined.

Here is the datagrid:

            <asp:DataGrid ID="grdPage" runat="server" AlternatingItemStyle-CssClass="row2"
            AutoGenerateColumns="false" BorderColor="#88B2C8" CellPadding="2" DataKeyField="row_id"
            GridLines="Both" HeaderStyle-CssClass="header" ItemStyle-CssClass="row1" OnItemCommand="page_OnItemCommand"
            Width="100%">
            <Columns>
                <asp:BoundColumn DataField="row_id" HeaderText="#"></asp:BoundColumn>
                <asp:BoundColumn DataField="col1" HeaderText="col1"></asp:BoundColumn>
                <asp:BoundColumn DataField="col2" HeaderText="col2"></asp:BoundColumn>
                <asp:BoundColumn DataField="col3" HeaderText="col3"></asp:BoundColumn>
                <asp:BoundColumn DataField="col4" HeaderText="col4"></asp:BoundColumn>
                <asp:BoundColumn DataField="col5" HeaderText="col5"></asp:BoundColumn>
                <asp:BoundColumn DataField="col6" HeaderText="col6"></asp:BoundColumn>
                <asp:BoundColumn DataField="col7" HeaderText="col7"></asp:BoundColumn>
                <asp:BoundColumn DataField="col8" HeaderText="col8"></asp:BoundColumn>
                <asp:BoundColumn DataField="col9" HeaderText="col9"></asp:BoundColumn>
                <asp:BoundColumn DataField="col10" HeaderText="col10"></asp:BoundColumn>
                <asp:TemplateColumn HeaderText="Actions" ItemStyle-HorizontalAlign="Right">
                    <ItemTemplate>
                        <asp:LinkButton SkinID="cmdEdit"  ID="cmdEdit" CommandName="Edit" runat="server" />
                        <asp:LinkButton SkinID="cmdDelete" ID="cmdDelete" CommandName="Delete" runat="server"  />
                    </ItemTemplate>
                </asp:TemplateColumn>
            </Columns>
        </asp:DataGrid>

I only have two items in the .skin file for link buttons:

<asp:LinkButton runat="server" SkindID="cmdEdit" Text="<img border=0 src='App_Themes/page1/images/cmdEdit.gif'/>"></asp:LinkButton>
<asp:LinkButton runat="server" SkindID="cmdDelete" Text="<img border=0 src='App_Themes/page1/images/cmdDelete.gif'/>"></asp:LinkButton>

Why does it tell me that is has already a default?

Is it possible to use skin files within itemtemplates and if not, how can I add this itemtemplaate diagrammatically to my the datagrid?

Thanks, Patrick