Rendering error messages for form_tag that creates one model multiple times like form_for?

_fields.html.erb

        
   <%= f.text_field :name %>
   <%= f.text_field :price %>
   <%= f.text_field :product_store %>
   	

form.html.erb

<%= form_tag create_multiple_products_path, :method => :post do %>
	<%= error_messages_for @product  %>	
          
           # the :purchase_date and :send_to_data are merged into all 5 Products.
            <%= date_select("product", "purchase_date")  %> 
	    
            <%= label_tag :send_to_data, 'Send to Data?' %>
	    <%= radio_button("product", :send_to_data, 1) %>
            <%= radio_button("product", :send_to_data, 0) %>
		
            <% @products.each_with_index do |product, index| %>
               <%= fields_for "products[#{index}]", product do |p| %>
                   <%= render "fields", :f => p %>
               <% end %>
            <% end %>

       <%= submit_tag "Done" %>
<% end %>

product.rb

class Product < ActiveRecord::Base
  attr_accessible :price, :name, :purchase_date, :product_store, :send_to_data
  belongs_to :user
  belongs_to :store
  attr_reader :product_store
  validates_inclusion_of :send_to_data, :in => [true, false]
  validates_presence_of :name, :price, :store_id, :user_id
  validates_numericality_of :price

  def product_store=(id)
    self.store_id = id
  end
end

products_controller.rb

class ProductsController < ApplicationController

  def new
    @products = Array.new(5) { Product.new }
  end

  def create_multiple
    @products = current_user.products.create(params[:products].map { |_k, up| up.merge params[:product] })
    respond_to do |format|
      if @products.all?(&:valid?)
        @products.each(&:save!)
        format.html { redirect_to :back, :notice => "Success!" }
        format.xml  { render :xml => @product, :status => :created, :location => @product }
      else
        format.html { redirect_to :back, :notice => "An error occured, please try again." }
        format.xml  { render :xml => @product.errors, :status => :unprocessable_entity }
      end
    end
  end
end