Save customer information and auto login

Hi Everyone,

I want save a guest customer information and auto login. But I am failure.

customer = this.CustomerService.AddCustomer(address.Email, address.FirstName, password, false, false, true, out status);
bool isLogin= this.CustomerService.Login(customer.Email, password);

The isLogin is true. But doesn't login the user . and the NopContext.Current.User is changed to null

How can I login as us?
I am using version 1.9

Thanks,
Willam

I solved. I  have spent so much time on this.

                bool isLogin= this.CustomerService.Login(customer.Email, password);
                if(isLogin)
                   FormsAuthentication.SetAuthCookie(customer.Email, false);

Thanks,
Willam