Here's the right way to do it, via an extension:
PHP:
if ( Yii::app()->apps->isAppName('customer') ) {
Yii::app()->hooks->addAction('controller_action_save_data', function($collection){
if ( $collection->controller->id != 'lists' || $collection->controller->action->id != 'create' ) {
return;
}
if ( ! $collection->success ) {
return;
}
$list = $collection->list;
$collection->controller->redirect(array('list_import/index', 'list_uid' => $list->list_uid));
});
}
You can put this code in an extension, or you can create a file in apps called custom-init.php and place it there.
This is also safe at upgrades.