<asp:Table id= "Table1" >
  <asp:TableRow >
        <asp:TableCell >
           ---------------- Здесь вложеная таблица -----
 
	 <asp:Table id= "Table2"  >
	    <asp:TableRow >
		<asp:TableCell >
		</asp:TableCell>
	    </asp:TableRow >			
              </asp:Table>
            -------------------------------------------------
 
         </asp:TableCell>
     </asp:TableRow>
     <asp:TableRow >
	<asp:TableCell>
                    Cell  1 
             </asp:TableCell>
	
            <asp:TableCell >
                    Cell  2 
            </asp:TableCell>
     </asp:TableRow>
</asp:Table>