Aggregated footer with LoadOnDemand not working

[Jiri]

Hi folks.

I have a treelist control on my page where I load the items dynamicaly. At each section I'd like to have aggregated sums at the bottom. I thing I have all set correctly regarding online demos but the result footer are all empty.

I use this code:

     <telerik:RadTreeList ID="rtlData" AllowLoadOnDemand="true" runat="server" AutoGenerateColumns="false"
         OnChildItemsDataBind="RadTreeList_ChildItemsDataBind" OnNeedDataSource="RadTreeList_NeedDataSource"
          DataKeyNames="CssClass,ParentId" ParentDataKeyNames="CssClass,ParentId" OnItemCreated="RadTreeList_ItemCreated"
         OnItemDataBound="RadTreeList_ItemDataBound" ShowFooter="true">
          <Columns>
               <telerik:TreeListBoundColumn DataField="ProductCatL3" UniqueName="ProductCatL3" HeaderText="Produkt L3">
               </telerik:TreeListBoundColumn>
               <telerik:TreeListBoundColumn DataField="ProductCatL2" UniqueName="ProductCatL2" HeaderText="Produkt L2">
               </telerik:TreeListBoundColumn>
               <telerik:TreeListBoundColumn DataField="ProductCatL1" UniqueName="ProductCatL1" HeaderText="Produkt L1">
               </telerik:TreeListBoundColumn>
               <telerik:TreeListBoundColumn DataField="State" UniqueName="State" HeaderText="Stav" DataType="System.Decimal" DataFormatString="{0:C2}" Aggregate="Sum">
               </telerik:TreeListBoundColumn>
               <telerik:TreeListBoundColumn DataField="Avg1Month" UniqueName="Avg1Month" HeaderText="Průměr 1 měsíc" DataFormatString="{0:C2}" Aggregate="Avg">
               </telerik:TreeListBoundColumn>
               <telerik:TreeListBoundColumn DataField="Avg3Months" UniqueName="Avg3Months" HeaderText="Průměr 3 měsíce" DataFormatString="{0:C2}" Aggregate="Avg">
               </telerik:TreeListBoundColumn>
               <telerik:TreeListBoundColumn DataField="ApprovedLimit" UniqueName="ApprovedLimit" HeaderText="Schválený limit" DataFormatString="{0:C2}" Aggregate="Sum">
               </telerik:TreeListBoundColumn>
               <telerik:TreeListBoundColumn DataField="CssClass" UniqueName="Css" HeaderText="CSS" Visible="false">
               </telerik:TreeListBoundColumn>
               <telerik:TreeListBoundColumn DataField="ParentId" UniqueName="ParentId" HeaderText="ParentId" Visible="false">
               </telerik:TreeListBoundColumn>
          </Columns>
     </telerik:RadTreeList>

What am I doing wrong that no footer are calculated and it only shows empty fields?

Sincerely
Scarlaxx