Cancel ASP.Net CreateUserWizard Step if Captcha code is invalid

This way

    <asp:CreateUserWizard ID="CreateUserWizard1" runat="server" OnCreatingUser = "CreateUserWizard1_CreatedUser">
        <WizardSteps>
            <asp:CreateUserWizardStep ID="CreateUserWizardStep1" runat="server">
                <ContentTemplate>
                <asp:TextBox runat = "server" ID = "Answer" />
                <asp:TextBox runat = "server" ID = "Question" />
                <asp:TextBox runat = "server" ID = "Email" />
                <asp:TextBox runat = "server" ID = "Password" />
                <asp:TextBox runat = "server" ID = "UserName" />
                    <cc1:CaptchaControl ID="Captcha1" runat="server" CaptchaBackgroundNoise="Medium"
                        CaptchaLength="5" CaptchaHeight="55" CaptchaWidth="200" CaptchaLineNoise="None"
                        CaptchaMinTimeout="5" CaptchaMaxTimeout="240" FontColor="#FF33CC" CaptchaFontWarping="Medium" />
                    <asp:TextBox runat="server" ID="txtCaptcha" />
                    <asp:Label ID="lblError" runat="server" Text="Invalid captcha" Visible = "false"></asp:Label>       

                </ContentTemplate>
            </asp:CreateUserWizardStep>
        </WizardSteps>
    </asp:CreateUserWizard>

    protected void CreateUserWizard1_CreatedUser(object sender, LoginCancelEventArgs e)
    {
        MSCaptcha.CaptchaControl Captcha1 = (CreateUserWizardStep1.ContentTemplateContainer.FindControl("Captcha1") as MSCaptcha.CaptchaControl);
        TextBox txtCaptcha = (TextBox)CreateUserWizardStep1.ContentTemplateContainer.FindControl("txtCaptcha");
        Captcha1.ValidateCaptcha(txtCaptcha.Text);
        if (!Captcha1.UserValidated)
        {
            CreateUserWizardStep1.ContentTemplateContainer.FindControl("lblError").Visible = true;
            e.Cancel = true;
            return;
        }
        //Save user to database here
    }