how to move 'delete row' menu item to bottom of context menu?

private void RadGridView1_ContextMenuOpening(object sender, ContextMenuOpeningEventArgs e)
{
    RadMenuItem mniProcess = new RadMenuItem();
    RadMenuItem mniVendorInquiry = new RadMenuItem();
    RadMenuSeparatorItem mniSeparate = new RadMenuSeparatorItem();

    e.ContextMenu.Items[0].Visibility = ElementVisibility.Collapsed;
    e.ContextMenu.Items[1].Visibility = ElementVisibility.Collapsed;

    mniProcess.Text = "Process PO";
    mniVendorInquiry.Text = "Vendor Inquiry";
    //e.ContextMenu.Items.Add(mniSeparate);
    RadMenuItem deleteRow = e.ContextMenu.Items[2] as RadMenuItem;
    e.ContextMenu.Items.Add(mniVendorInquiry);
    e.ContextMenu.Items.Add(mniProcess);
    e.ContextMenu.Items.RemoveAt(2);
    e.ContextMenu.Items.Add(deleteRow);

    try
    {
        mniProcess.Click += mniProcess_Click;
        mniVendorInquiry.Click += mniVendorInquiry_Click;
    }
    catch (Exception)
    {
    }
}