Retrieving Values from Dynamically Generated Texboxes

Hi, I've read numerous posts regarding this issue, but no joy.
I create textboxes in codebehind based on user choice from a dropdown. The user then fills in thevalues of those textboxes and clicks a linkbutton to save the values. When I try to access those textbox values, they are null.
Thank you for any help!


aspx code:  <asp:PlaceHolder runat="server" id="TextBoxesHere" />


VB Code:
Private Sub CreateTextBoxes()

        Dim ct As Integer = ddlAYIntervals.SelectedValue
      
        TextBoxesHere.Controls.Add(New LiteralControl("<br><table id=""NewIntervals""><tr><th>Interval Name</th><th>Start Date</th><th>End Date</th></tr>"))
        ' now, cre ...