I think you just have to do a load of "if then"'s

       <tr>
        <td valign="middle" class="text">
         <% if (staff){ %>
         <asp:Button id="Button1" class="edititem" runat="server" Text='<%# ((string)DataBinder.Eval(Container.DataItem, "itemid")).Trim()%>' onmouseover="this.className='edititemover'" onmouseout="this.className='edititem'" commandname="Edit" />
         <% } else { %>
         <%# DataBinder.Eval(Container.DataItem, "itemid")%>
         <% } %>
        </td>
    </tr>

is what I did once upon a time.

Also a neat trick is

<%# MySupp((string)DataBinder.Eval(Container.DataItem, "suppname"))%>

where MySupp is a function and so you can generate a load of <tr><td>'s from code behind based on the bound value "suppname".