Not sure why it won't outside the list, but in the list you likely need to do a recursive search.  Also you will need to be able to collect more than one label.  Here's a snippet of code where I am doing something similar.  -

Like in previos post I use recursive functions for situations this. I did wrote function (a long time ago :-) you can use it for your case. I think it fit perfectly for your needs. Input module control as root (but this can be page control also):

      ''' <summary>
        ''' Return control or any child with specified id .
        ''' </summary>
        ''' <param name="Root">ControlID or list of possible controlIDs separated with semicolon.</param>
        ''' <param name="Id"></param>
        ''' <returns></returns>
        ''' <remarks></remarks>
        Public Function FindControl(ByVal Root As Control, ByVal Id As String) As Control
            Dim ids() As String = Split(Id, ";")
            Dim currentId As String
            For Each currentId In ids
                If LCase(Root.ID) = LCase(currentId) Then
                    Return Root
                End If
            Next
            Dim Ctl As Control
            For Each Ctl In Root.Controls
                Dim FoundCtl As Control = FindControl(Ctl, Id)
                If Not FoundCtl Is Nothing Then
                    Return FoundCtl
                End If
            Next
            Return Nothing
        End Function