ho risolto con un literal

codice:
 Sub Crea_Risposte()
        If lstRisposte.Items(lstRisposte.SelectedIndex).Value() <> "-1" Then
            Dim txt As TextBox
            Dim lbl As Label
            Dim lit As New Literal()

            Dim i As Int16

            For i = 1 To lstRisposte.Items(lstRisposte.SelectedIndex).Value()
                txt = New TextBox()
                lbl = New Label()
                lit = New Literal()

                lit.Text = "
"
                lbl.Text = "Risposta N° " & i & ":
"
                lblrisposte.Controls.Add(lbl)
                txtrisposte.Controls.Add(txt)
                txtrisposte.Controls.Add(lit)
            Next
        End If
    End Sub