Help with authlogin gem

I am puzzled over how to normalize the login value provided by the user
to authlogic to validate the existence of that user. I have threaded
my way through the code and tried to understand what it and the examples
are trying to tell me but I am just not making the connections.

Basically I have this in the login (user_sessions_controller):

  def new
    @user_session = UserSession.new
  end

  def create
    @user_session = UserSession.new(params[:user_session])
    # debugger if ENV['RAILS_ENV'] == 'development'
    @user_session.save do |result|
      if result
        flash[:notice] = "Welcome"
        redirect_back_or_default account_url
      else
        render :action => :new
      end
    end
  end

What I want to do is modify the input value of the login identity field
before the User.find is performed. It seems that this should be
possible in the User model.

Inside authlogic/session.config.rb I find this:

        # Authlogic tries to validate the credentials passed to it. One
part
        # of validation is actually finding the user and making sure it
        # exists. What method it uses the do this is up to you.

James Byrne wrote:

I am puzzled over how to normalize the login value provided by the user
to authlogic to validate the existence of that user. I have threaded
my way through the code and tried to understand what it and the examples
are trying to tell me but I am just not making the connections.

This seems to be the place where the problem lies:

[150, 159] in
/usr/lib/ruby/gems/1.8/gems/authlogic-1.3.7/lib/authlogic/session/base.rb
   150 def credentials=(values)
   151 return if values.blank? || !values.is_a?(Hash)
   152 values.symbolize_keys!
   153 values.each do |field, value|
   154 next if value.blank?
=> 155 send("#{field}=", value)
   156 end
   157 end
   158
   159 # Resets everything, your errors, record, cookies, and
session. Basically "logs out" a user.
/usr/lib/ruby/gems/1.8/gems/authlogic-1.3.7/lib/authlogic/session/base.rb:155
send("#{field}=", value)
(rdb:6) v l
  field => "username"
  value => "MYUSER"
  values => {"username"=>"MYUSER", "password"=>"mypassword",
"remember_me"=>"0"}

   361
   362 attr_reader :#{login_field}
   363
=> 364 def #{login_field}=(value)
   365 self.authenticating_with = :password
   366 @#{login_field} = value
   367 end
   368
/usr/lib/ruby/gems/1.8/gems/authlogic-1.3.7/lib/authlogic/session/base.rb:364
def #{login_field}=(value)
(rdb:6) v l
  value => "MYUSER"

When the Session::Base code hits line 366 then the direct assignment of
the @params value of the login_field to the corresponding instance value
simply bypasses the setter defined in the User model, does it not?

Given this construction I cannot see a way to invoke the model's setter
method for the login field. Am I missing something?