activemerchant- how set up my code, what I want for paypal recurring payments

paypal_recurring_api_activemerchant

This is how I set up my gateway in environment file (config/environment/development):
config.payment_gateway = ActiveMerchant::Billing::PaypalGateway.new(
      :login => 'rander_1307553309_biz_api1.glideint.com',
      :password => '1307553332',
      :signature => 'AiCozzWYgDEkMhTodrzOjnIvAbX.AQp38EXocUyf0PKAjIPmXhTGJHKv')

I call the method to capture funds (after credit card is valid)

response = Rails.config.application.payment_gateway.capture();  // this is working in my app

I want to do:

response = Rails.config.application.payment_gateway.recurring() (a method that lives in the included file paypal_recurring_api.rb) 

but I get unknown method recurring. I have tried calling the paypal api directly, but then it is uninstantiated constant PaypalRecurringApi

This is the gateway I am using: http://rubydoc.info/github/Shopify/active_merchant/master/ActiveMerchant/Billing/PaypalGateway

which includes:
http://rubydoc.info/github/Shopify/active_merchant/master/ActiveMerchant/Billing/PaypalRecurringApi

I want to access the method recurring inside this PaypalRecurringApi