Example of container aware migration

MigrationExample.php

<?php

namespace Application\Migrations;

use Doctrine\DBAL\Migrations\AbstractMigration,
    Doctrine\DBAL\Schema\Schema;

class Version20120920130854 extends AbstractMigration
{
    public function up(Schema $schema)
    {
        // ...

        $container = $this->version->getConfiguration()->getContainer();
        $em = $container->get('doctrine.orm.entity_manager');
        
        // ... use EntityManager and other services
    }

    public function down(Schema $schema)
    {
        // ...
    }
    
}

I had the same issue because of using sf 2.0 and not integrated in 2.0.x-dev of composer package.

You can apply the pull request in your own fork/version to have this working.