Accepts nested attributes for not working

gistfile1.rb

# models/delivery.rb
class Delivery < ActiveRecord::Base
	has_one :order
	has_one :customer, :through => :order
	accepts_nested_attributes_for :order
	
	attr_accessible :note, :position, :crew_ids, :order_attributes
end

# models/order.rb
class Order < ActiveRecord::Base
	belongs_to :customer
	belongs_to :delivery
	
	attr_accessible :amount, :crew_required, :customer_id, :delivery_id
	
	validates_presence_of :customer_id, :amount, :crew_required	
end

# controllers/deliveries_controller.rb
class DeliveriesController < ApplicationController
	respond_to :json
	
	def index
		@deliveries = Delivery.include_crew_order_customer
	end
	
	def update
		@delivery = Delivery.find params[:id]
		if @delivery.update_attributes params
			render "deliveries/show"
		else
			respond_with @delivery
		end
	end
		
end

#params look like this
{"id"=>"3", "position"=>3, "note"=>nil, "crew_ids"=>[], "crew"=>[], "order_attributes"=>{"id"=>1003, "customer_id"=>3, "delivery_id"=>nil, "amount"=>2500, "crew_required"=>3}}