Cannot update a property in an embedded Array in mongoose - node.js

Question

I'm working on a commenting system with mongoose/n,
users can comment, and like in reddit, users should vote each comment up or down.
and i have the following comment scheme:
var commentSchema = new Schema({
text: String,
level: { type: Number, min: 0, max: 30, default: 0},
slug: String,
full_slug: String,
discussion_id: { type: Schema.ObjectId, ref: 'Uranus' },
parent_id: {type: Schema.ObjectId,ref: 'Comment'},
score: [{
upvote: {type: Number,min: 0,max: 9000},
downvote: {type: Number,min: 0,max: 9000},
voter: {type: Schema.ObjectId,ref: 'Account'}
}],
updated: { type: Date, default: Date.now },
created: { type: Date, default: Date.now },
author: { type: Schema.ObjectId, ref: 'Account' },
});
it works just fine, but i have no clue, how to update the score-array. it just doesn't work.
Here is the sample json-data i got:
{
"__v" : 0,
"_id" : ObjectId("52a0d4ff779edff16d000006"),
"author" : ObjectId("529dfdda6b2d7a450c000009"),
"created" : ISODate("2013-12-05T19:33:19.229Z"),
"discussion_id" : ObjectId("529f7b04cbab31cc3e000004"),
"full_slug" : "2013.12.05.19.33.19:e1CDx79g8",
"level" : 0,
"score" : [
{
"upvote" : 1,
"downvote" : 0,
"voter" : ObjectId("529dfdda6b2d7a450c000009"),
"_id" : ObjectId("52a0d4ff779edff16d000007")
},
{
"upvote" : 0,
"downvote" : 1,
"voter" : ObjectId("52a0d9883027a89d6e000002"),
"_id" : ObjectId("52a0d9903027a89d6e000004")
},
{
"upvote" : 0,
"downvote" : 1,
"voter" : ObjectId("52a0d99a3027a89d6e000005"),
"_id" : ObjectId("52a0d9a63027a89d6e000007")
}
],
"slug" : "e1CDx79g8",
"text" : "A Comment",
"updated" : ISODate("2013-12-05T19:33:19.229Z")
}
so, i just update the comment by
var query = {
'score.voter': mongoose.Types.ObjectId(String('52a0d9883027a89d6e000002'))
};
Comment.update( query, {$set: {"score.$.upvote": 10}} )
The problem is, that it's just not updating.
i know, there are a few other questions regarding this problem, but all solutions are not working for me. i hope someone can help me.
UPDATE:
Found the problem, Seems like you have to have a callback on the update function like this:
Comment.update( query, {$set: {"score.$.upvote": 10}}, { multi: false }, function(err,n){
console.log("affected rows:", n)
});