Live preview in rails 2.0

I'am trying to set a live preview for my rails app
I using recipe 3 from rails recipies.
It's a recipe from rails 1.0 in 2.0 i get no live preview

in my testapp i have the following code


def new
  @Post =

def preview
render :layout => false

class Post < ActiveRecord::Base
  attr_accessor :title, :body

view new.rhtml

  <%= javascript_include_tag "prototype"%>

<% form_for :post, @post, :url=> {:action => 'create', :id =>
"entry-form" } do |f| %>

<%= f.text_field :title %></p>

  <%= f.text_area :body %>
<%= submit_tag "Post" %>
<% end %>

<%= observe_form "post-form",
:update => "live_preview",
:complete => "'live-preview')",
:url => { :action => "preview" }

<div id="live-preview" style="display: none; border: 1px solid">




<%= textilize params[:page][:body]%>

I got no preview i got nothing.
The only difference in my code and the book i have is into the new.rhtml
because start_form_tag
does not longer exists in 2.0

For now the log gets all the new information from the preview.
But i got nothing on screen only a black line

This is into my log

Processing HomeController#preview (for at 2008-02-01 13:38:28)
  Session ID:
  Parameters: {"commit"=>"Post", "post"=>{"title"=>"",
"action"=>"preview", "controller"=>"home"}
Rendering home/preview
  Post Columns (0.003355) SHOW FIELDS FROM `posts`
Completed in 0.01117 (89 reqs/sec) | Rendering: 0.00172 (15%) | DB:
0.00336 (30%) | 200 OK []

In my view i have this

<%= observe_form "post-form",
:frequency => 1,
:update => "live_preview",
:complete => "'live-preview')",
:url => { :action => "preview" }

<div id="live-preview" style="display: none; border: 1px solid"></div>

but the div gives no result of the preview method