Connecting to the vBulletin database

My vBulletin mysql database is separate from the Drupal 7 database, so I'm connecting to it at the top of each of my migrate .inc files, using something like

    Database::addConnectionInfo('for_user_migration', 'default', array(
      'driver' => 'mysql',
      'database' => 'mysite_vbdatabase',
      'username' => 'mysite_d7user',
      'password' => 'myd7userpassword',
      'host' => 'localhost',
      'prefix' => 'vb_',
    ));

Basically, I've copied the vBulletin database onto the same localhost server as my Drupal 7 database. I then used phpMyAdmin to make sure that my Drupal 7 user has full access to the vBulletin database.

Finally, I've made sure the above code includes the prefix from the tables in the vBulletin database, which is typically vb_ or vb3_ but it's fairly obvious when looking at the phpMyAdmin tables