Recently I had an issue where I needed to call another email method and not use the STMP settings in the Wizard Control. 

I send an email to have the user verify their account using the CreateUserWizard SendingEmail Event. This works great by using the email setup in the control.

In order to override the send email event I issued a return statement in the SendingMail event handler.

protected void CreateUserWizard1_SendingMail(object sender, MailMessageEventArgs e)
{
return; . . .

Next I created an event after the user was created using oncreateduser="CreateUserWizard1_CreatedUser"

Now in the CreateUserWizard1_CreatedUser method I send the registration email to the new user.

 protected void CreateUserWizard1_CreatedUser(object sender, EventArgs e)
{
OverideWizardEmail();
}  

private void OverideWizardEmail()
{ 
MembershipUser UserInfo = Membership.GetUser(CreateUserWizard1.UserName);
string VerifyURL = string.Empty;
..... send email