Treebook + Messaging // before_create callback not triggering

class Message < ActiveRecord::Base
 belongs_to :author, :class_name => "User"
 has_many :message_copies
 has_many :recipients, :through => :message_copies
 before_create :prepare_copies

 attr_accessor  :to
 attr_accessible :subject, :body, :to

 def prepare_copies
  return if to.blank?

  else
    to.each do |recipient|
      recipient = User.find(recipient)
      message_copies.build(:recipient_id => recipient.id, :folder_id => recipient.inbox.id)
  end
 end
end

class MessageCopy < ActiveRecord::Base
 attr_accessible :folder_id, :message_id, :recipient_id

 belongs_to :message
 belongs_to :recipient, :class_name => "User"
 belongs_to :folder
 delegate   :author, :created_at, :subject, :body, :recipients, :to => :message
end

class SentController < ApplicationController
  def index
    @messages = current_user.sent_messages.paginate :per_page => 10, :page => params[:page], :order => "created_at DESC"
  end

  def show
    @message = current_user.sent_messages.find(params[:id])
  end

  def new
    @message = current_user.sent_messages.build
  end

  def create
    @message = current_user.sent_messages.build(params[:message])

  if @message.save
    flash[:notice] = "Message sent."
    redirect_to :action => "index"
  else
    render :action => "new"
  end
 end
end

<%= simple_form_for :message, :url => {:controller => "sent", :action => "create"} do |f| %>

<p>
To:
<%= select_tag :to, options_from_collection_for_select(User.all, "id", "full_name", @message.to) %>
</p>

<p><%= f.input :subject %></p>
<p><br /> <%= f.input :body %></p>
<p><%= submit_tag "Send" %></p>
<% end %>

Started POST "/sent" for 127.0.0.1 at 2013-03-07 00:25:55 -0500
Processing by SentController#create as HTML
Parameters: {"utf8"=>"?", "authenticity_token"=>"xPMFbWdg0thopyoov3yAnEa+N6fTcFNOpzAaJgXazd4=", "to"=>"6", "message"=>{"subject"=>"twat", "body"=>"tee"}, "commit"=>"Send"}

User Load (0.8ms)  SELECT "users".* FROM "users" WHERE "users"."id" = 5 LIMIT 1

(0.2ms)  begin transaction

SQL (2.4ms)  INSERT INTO "messages" ("author_id", "body", "created_at", "subject", "updated_at") VALUES (?, ?, ?, ?, ?)  [["author_id", 5], ["body", "tee"], ["created_at", Thu, 07 Mar 2013 05:25:55 UTC +00:00], ["subject", "twat"], ["updated_at", Thu, 07 Mar 2013 05:25:55 UTC +00:00]]

(3.1ms)  commit transaction
Redirected to http://localhost:3000/sent
Completed 302 Found in 41ms (ActiveRecord: 6.4ms)