Virtual scrollpagging is not working

[Prab]

hi,
i am using radgrid with vitualscrolling in my application and i am using client side databinding to avoid postpack .if radgrid contains more than two pages ,radgrid working fine but if radgrid contains two pages, i am unable to view second page..becoz scroll is not working... please give some suggestion.The following codings are using in my application.

javascript:
function RadGrid1_Command(sender, args)
{
args.set_cancel(true);
var currentPageIndex = sender.get_masterTableView().get_currentPageIndex();
var pageSize = sender.get_masterTableView().get_pageSize();
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}
function updateGrid(result) {
var tableView = $find(document.getElementById("hdnradgridclientid").value).get_masterTableView();
tableView.set_dataSource(result);
tableView.dataBind();
}
function updateVirtualItemCount(result)
{
var tableView = $find(document.getElementById("hdnradgridclientid").value).get_masterTableView();
tableView.set_virtualItemCount(result);
}       

aspx page:

<telerik:RadGrid ID="RadGridAssessment" EnableViewState="false" Width="100%" runat="server"
 AllowSorting="True" Height="430px" AllowMultiRowSelection="true" AllowPaging="true"GridLines="None" BorderWidth="0" AutoGenerateColumns="true" PagerStyle-AlwaysVisible="false"Skin="Vista" OnNeedDataSource="RadGrid1_NeedDataSource">
<PagerStyle Visible="false" />
<MasterTableView Width="99%">
</MasterTableView>
<ClientSettings EnableRowHoverStyle="true">
<ClientEvents OnCommand="RadGrid1_Command" />
<Selecting AllowRowSelect="True"></Selecting>
<Scrolling AllowScroll="true" EnableVirtualScrollPaging="true" UseStaticHeaders="true"ScrollHeight="275px" SaveScrollPosition="True">
</Scrolling>
</ClientSettings>
 </telerik:RadGrid>


[Prab]

please help me to solve this problem.........