You can easily achive by calling CreateUser method instead of using CreateUserWizard.
<asp:TextBox ID="EmailTextBox" runat="Server" />
<asp:TextBox ID="PasswordTextBox" runat="Server" />
<asp:TextBox ID="PasswordQuestionTextBox" runat="Server" />
<asp:TextBox ID="PasswordAnswerTextBox" runat="Server" />
string username = EmailTextBox.text; // Same as email
string password = PasswordTextBox.text;
string email = EmailTextBox.text;
string passwordQuestion = PasswordQuestionTextBox.text;
string passwordAnswer = PasswordAnswerTextBox.text;
bool isApproved = true;
MembershipCreateStatus status;
MembershipUser membershipUser = System.Web.Security.Membership.CreateUser(username, password, email, passwordQuestion, passwordAnswer, isApproved, out status);
if (status != MembershipCreateStatus.Success)
throw new Exception(status.ToString());