diff --git a/README.markdown b/README.markdown
index 1437f60..455dfcc 100644
--- a/README.markdown
+++ b/README.markdown
@@ -9,95 +9,102 @@ It's a Ruby on Rails port of the connexion kits published by the bank.
 
 ## INSTALL
 
-    script/plugin install git://github.com/novelys/paiementcic.git
-
-or, in your Gemfile
-
     gem 'paiement_cic'
 
 ## USAGE
 
-### in environment.rb :
+### in an initializer (`config/initializers/paiement_cic.rb`) :
 
-    # here the hmac key calculated with the js calculator given by CIC
-    PaiementCic.hmac_key = "########################################"
-    # Here the TPE number
-    PaiementCic.tpe = "#######"
-    # Here the Merchant name
-    PaiementCic.societe = "xxxxxxxxxxxxx"
+```ruby
+PaiementCic.configure do |config|
+  # here the hmac key calculated with the js calculator given by CIC
+  config.hmac_key = "########################################"
+  # Here the TPE number
+  config.tpe = "#######"
+  # Here the Merchant name
+  config.societe = "xxxxxxxxxxxxx"
 
-### in development.rb :
+  # You can specify the target URL
+  config.target_url = "https://ssl.paiement.cic-banques.fr/test/paiement.cgi"
+  # Or used predefined ones by specifying environment and bank
+  config.bank = :cm # or :cic
+  config.env = :test # or :production
+end
+```
 
-    PaiementCic.target_url = "https://ssl.paiement.cic-banques.fr/test/paiement.cgi" # or https://paiement.creditmutuel.fr/test/paiement.cgi
-
-### in production.rb :
-
-    PaiementCic.target_url = "https://ssl.paiement.cic-banques.fr/paiement.cgi" # or https://paiement.creditmutuel.fr/paiement.cgi
-
-### in order controller :
-
-    helper :'paiement_cic/form'
+You can also specify `hmac_key`, `tpe` and `societe` when initializing `PaiementCic::TPE` and with `paiement_cic_hidden_fields` helper by passing an hash.
+```ruby
+{
+  hmac_key: "########################################",
+  tpe: "#######",
+  societe: "xxxxxxxxxxxxx",
+}
+```
 
 ### in the payment by card view :
 
-    - form_tag PaiementCic.target_url do
-      = paiement_cic_hidden_fields(@order, @order_transaction, :url_retour => edit_order_url(order), :url_retour_ok => bank_ok_order_transaction_url(order_transaction), :url_retour_err => bank_err_order_transaction_url(order_transaction))
-      = submit_tag "Accéder au site de la banque", :style => "font-weight: bold;"
-      = image_tag "reassuring_pictograms.jpg", :alt => "Pictogrammes rassurants", :style => "width: 157px;"
+```
+- form_tag PaiementCic.target_url do
+  = paiement_cic_hidden_fields(@order.reference, @order.amount, mail: 'email@example.com', url_retour: edit_order_url(order), url_retour_ok: bank_ok_order_transaction_url(order_transaction), url_retour_err: bank_err_order_transaction_url(order_transaction))
+  = submit_tag "Accéder au site de la banque", :style => "font-weight: bold;"
+  = image_tag "reassuring_pictograms.jpg", :alt => "Pictogrammes rassurants", :style => "width: 157px;"
+```
 
 ### in a controller for call back from the bank :
 
-    class OrderTransactionsController < ApplicationController
+```ruby
+class OrderTransactionsController < ApplicationController
 
-      protect_from_forgery :except => [:bank_callback]
+  protect_from_forgery :except => [:bank_callback]
 
-      def bank_callback
-        if PaiementCic.verify_hmac(params)
-          order_transaction = OrderTransaction.find_by_reference params[:reference], :last
-          order = order_transaction.order
+  def bank_callback
+    tpe = PaiementCic::TPE.new
 
-          code_retour = params['code-retour']
+    if tpe.verify_hmac(params)
+      order_transaction = OrderTransaction.find_by_reference params[:reference], :last
+      order = order_transaction.order
 
-          if code_retour == "Annulation"
-            order.cancel!
-            order.update_attribute :description, "Paiement refusé par la banque."
+      code_retour = params['code-retour']
 
-          elsif code_retour == "payetest"
-            order.pay!
-            order.update_attribute :description, "TEST accepté par la banque."
-            order_transaction.update_attribute :test, true
-
-          elsif code_retour == "paiement"
-            order.pay!
-            order.update_attribute :description, "Paiement accepté par la banque."
-            order_transaction.update_attribute :test, false
-          end
-
-          order_transaction.update_attribute :success, true
-      
-          receipt = "0"
-        else
-          order.transaction_declined!
-          order.update_attribute :description, "Document Falsifie."
-          order_transaction.update_attribute :success, false
-
-          receipt = "1\n#{PaiementCic.mac_string}"
-        end
-        render :text => "Pragma: no-cache\nContent-type: text/plain\n\nversion=2\ncdr=#{receipt}"
-      end
-
-      def bank_ok
-        @order_transaction = OrderTransaction.find params[:id]
-        @order = @order_transaction.order
-        @order.pay!
-      end
-
-      def bank_err
-        order_transaction = OrderTransaction.find params[:id]
-        order = order_transaction.order
+      if code_retour == "Annulation"
         order.cancel!
+        order.update_attribute :description, "Paiement refusé par la banque."
+
+      elsif code_retour == "payetest"
+        order.pay!
+        order.update_attribute :description, "TEST accepté par la banque."
+        order_transaction.update_attribute :test, true
+
+      elsif code_retour == "paiement"
+        order.pay!
+        order.update_attribute :description, "Paiement accepté par la banque."
+        order_transaction.update_attribute :test, false
       end
+
+      order_transaction.update_attribute :success, true
+
+      receipt = "0"
+    else
+      order.transaction_declined!
+      order.update_attribute :description, "Document Falsifie."
+      order_transaction.update_attribute :success, false
+
+      receipt = "1\n#{tpe.mac_string}"
     end
+    render :text => "Pragma: no-cache\nContent-type: text/plain\n\nversion=2\ncdr=#{receipt}"
+  end
+
+  def bank_ok
+    @order_transaction = OrderTransaction.find params[:id]
+    @order = @order_transaction.order
+  end
+
+  def bank_err
+    order_transaction = OrderTransaction.find params[:id]
+    order = order_transaction.order
+  end
+end
+```