Mongoose does not populate virtuals? :(

gistfile1.js

var mongoose = require('mongoose');
var Schema = mongoose.Schema;

var UserSchema = new Schema({
  name: {
    first: {
      type: String
    },
    last: {
      type: String
    }
  }
});

User
.virtual('name.full')
.get(function () {
  return [this.name.first, this.name.last].join(' ');
});


var ItemSchema = new Schema({
  owner: {
    type: Schema.ObjectId,
    ref: 'User'
  }
});


var ItemModel = mongoose.model('User', UserSchema);

ItemModel
.findById(id)
.populate('owner')
.run(function (err, item) {
  console.log(item.user.full); // == undefined
});