pre save hook: how is the sequence of callbacks in mongoose

I would like to increment a counter in my pre save callback. I found this stackoverflow really useful to do so: Has Mongoose support findAndModify Mongodb method?

What I would likt to do is use the findAndModify method. But when I implement the statics my squence of callbacks is not as expected. I do always and pre save and then execute findAndModify but I would like do execute findAndModify in between start and end of the pre save hook. If I define a general method with a callback it works as expected.

worked also with the done parameter of the pre-save hook without any different result

What do I miss here

My code looks like this:

var mongoose = require('mongoose');
var should = require('should');

mongoose.connect("localhost","test_db");

var CommentSchema = new mongoose.Schema({
  content:    {type:String},
  created_at: {type:Date, default:Date.now},
  _post:{type:mongoose.Schema.ObjectId,ref:'Post'}

});

var PostSchema = new mongoose.Schema({
  title:    {type:String},
  content:  {type:String},
  comments: [{type:mongoose.Schema.ObjectId, ref:'Comment'}],
  counter: {type:Number}

    });

PostSchema.statics.findAndModify= function(query,sort,doc,options,callback){
  return this.collection.findAndModify(query,sort,doc,options,callback);
 }

PostSchema.statics.test_me = function(clb){
   console.log("test_me");
   clb();
}
CommentSchema.pre('save',function(next,done){
  console.log("enter pre save comment");
  if(this.isNew){
   Post.findAndModify({_id:this._post},[],{$inc:{count:1}},{new:true},function(err,post){
    console.log("enter find-and-modify!");
    console.log(post);
   });
  Post.test_me(function(){
    console.log("callback of test_me");
  });
  console.log("exit pre save comment");

    next();
  }
});

var Post = mongoose.model('Post',PostSchema);
var Comment = mongoose.model('Comment',CommentSchema);

var post = new Post({title:"hello world"});
var comment = new Comment({content:"1st comment",_post:post});
post.comments.push(comment);

  var id = post.id;
  console.log(id);
  post.save(function(err){
    comment.save(function(err){
        Post.find({_id:id })
          .populate('comments')
          .exec(function(err,result){
          console.log("--------------- result -----------------");
          console.log(result);
          });
    });
  });

This is the result from my command-line:

5049f0d2e21547430a000001
enter pre save comment
test_me
callback of test_me
exit pre save comment
enter find-and-modify!
{ __v: 0,
  _id: 5049f0d2e21547430a000001,
  comments: [ 5049f0d2e21547430a000002 ],
  count: 1,
  title: 'hello world' }
--------------- result -----------------
[ { __v: 0,
    _id: 5049f0d2e21547430a000001,
    count: 1,
    title: 'hello world',
    comments: 
     [ { content: '1st comment',
         _post: 5049f0d2e21547430a000001,
         _id: 5049f0d2e21547430a000002,
         __v: 0,
         created_at: Fri Sep 07 2012 15:04:18 GMT+0200 (CEST) } ] } ]

EDIT: I do not want to know how to execute findAndModify with test_me in a sequence. I want to know why findAndMody enters after pre-saved is finished. Even it is embedded and should work as demonstrated with the test_me method. So the test_me method should illustrate that a async method should work nested... but findAndModify does not... like my command-line output shows...it always enters findAndModify after pre-save exits even when I use the done() callback...