[Rails 3.2] class in lib does not override class in engine

I am mounting the engine ‘opro_oauth’ gem in my routes

mount_opro_oauth

I want to overwrite a method from the engine lib: /lib/opro/auth_provider/devise.rb

module Opro
module AuthProvider
class Devise

def find_user_for_auth(params)

end
end
end
end

So, I added the modified devise.rb n my iapp , /lib/opro/auth_provider/devise.rb

and added config.autoload_paths += ["#{config.root}/lib/opro/auth_provider"] in my application.rb

I inserted a debigger statement to check if the method is reached but no way, the original method is always run… what’s wrong with my setup… ??

thanks for feedback