Custom Many To Many and Select2

[ndoulgeridis]

Hello,

I have successfully created a form of type afe_select2_entity with 2 entities having many-to-many relationship by doing:

 $builder->add('foo', 'afe_select2_entity', array(
        'class' => 'Foo\FooBundle\Entity\Foo',
        'multiple' => true,
        'label' => 'field.foo',

    ));

Now I have following entities:

1. Category
2. CategoryHasType
3. Type

How now from category form type embed a form to select types from Type entity and has afe_select2_entity styling? (autocomplete and boxes with icon to remove on selection)