Authlogic giving problem

Hi,
I have an application running.
I have exsting users which are created by using the "Restful
Authentication".
Right now we modified our autnentication to "Authlogic", due to that
our exsiting user are not able to login.
To solve this problem I went through this:-

http://www.binarylogic.com/2008/11/23/tutorial-easily-migrate-from-restful_authentication-to-authlogic/

And I have added the follwoing in my user.rb:-

  acts_as_authentic do |c|
    c.act_like_restful_authentication = true
  end

By adding that, exsiting users are able to login, but the new users
are not able to login.

Can anyone tell me that How should I tackle this problem?

Thanks,
Tushar