AssociatedControlID and User Controls

[Verticon::]

I have a user control that contains a drop down list and a few other
items. I have a label control on the form level. how do I assign the
label to the drop down list in the user control?

<asp:Label ID="Label" runat="server" AssociatedControlID=?></
asp:Label>

<UserControl ID="UserControl" runat="server">
<aspropDownList ID="Input" runat="server"></aspropDownList> //
Renders as "UserControl_Input"
</UserControl>