updating nested document with mongoDb + nodeJs

I have a structure like this:

{
    "_id" : ObjectId("501abaa341021dc3a1d0c70c"),
    "name" : "prova",
    "idDj" : "1",
    "list" : [
        {
            "id" : 1,
            "votes" : 2
        },
        {
            "id" : 2,
            "votes" : 4
        }
    ]
}

And I'm trying to increase votes with this query:

session_collection.update(
 {'_id':session_collection.db.bson_serializer.ObjectID.createFromHexString(idSession),'list.id':idSong},
 {$inc:{'list.$.votes':1}},
 {safe: true} ,
 callback);

But it doesn't work, there are no problems it just doesn't update anything.

I think it's because the ['] (simple quotation mark) on the 'list.id' and 'list.$.votes' because the same query inside the terminal works perfectly.

Thanks!