FindControl: Nested Controls

Hi I am trying to find 3 controls on a content page;
I 'Label', which I could find
and a  '<div>' and 'CheckBox' which I couldn't find.
<asp:Label runat="server" id="Label1" AssociatedControlID="CheckBox1" > <div ID="div1" runat="server"> <asp:CheckBox ID="CheckBox1" runat="server" /> </div> </asp:Label>



I could find the label, using this code...
Label lbl = this.Master.FindControl("MainContent").FindControl("Label1”) as Label;
And tried all of these to find the <div> and the same methods to try and find the checkbox...both unsucessfully
HtmlContainerControl div = this.Master.FindControl("div1”) as HtmlContainerControl; HtmlContainerControl div = (HtmlContainerControl)this.Master.FindControl("MainContent").FindControl("div1"); HtmlContainerControl div = ( ...