Placeholder on new textbox in CreateUserWizard

Hello
I have a createUserWizard with an additional textbox called forename.
But not sure how to give the forename textbox a placeholder <forename>
see vb below.
Imports System.Web.UI.WebControls.TextBox Imports System.IO Imports System.Net.Mail Imports System.Data.SqlClient Imports System.Data Imports System.Configuration Imports System.Net Partial Class SeekerRegister Inherits System.Web.UI.Page Protected Sub CreateUserWizard1_CreatingUser(ByVal sender As Object, ByVal e As LoginCancelEventArgs) Dim cuw As CreateUserWizard = CType(sender, CreateUserWizard) cuw.Email = cuw.UserName End Sub Protected Sub CreateUserWizard1_SendingMail(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.MailMessageEventArgs) Handles CreateUserWizard1.SendingMail Dim userInfo As MembershipUser = Membership.GetUser(CreateUserWizard1.UserName) ...