<?php
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $localizator = new Localizator();

        $builder
            ->add('name')
            ->add('country', 'entity', array(
                'class' => 'MyProject\Bundle\DemoBundle\Entity\Country',
                'property' => function ($country) use ($localizator) {
                    return $country->getName().' ('.$localizator->translate($country->getName()).')';
                }
                )
            )
        ;
    }