How to set application_fee to Stripe

[mikebase]

Hi! I am trying to set application_fee. Stripe docs say:

$charge = \Stripe\Charge::create(array(
  "amount" => 1000,
  "currency" => "eur",
  "source" => "tok_visa",
  "application_fee" => 123,
), array("stripe_account" => "{CONNECTED_STRIPE_ACCOUNT_ID}"));

In my app, I am setting additional stripe's fields with setDetails:

$storage = $this->get('payum')->getStorage('AppBundle\Entity\Payment');

$payment = $storage->create();
...
$payment->setDetails([
  'application_fee' => 123,
]);

But I have no idea how to set stripe_account (I have generated CONNECTED_STRIPE_ACCOUNT_ID correctly). Any combinations of setting Stripe's values return an error from api.

Thanks.

[yurguis]

I'm trying to use connected account from Stripe but I see that Payum's Stripe integration is not ready for it.
This is stripe-php's method signature for create:
protected static function _create($params = null, $options = null)
and stripe bundle is not passing any options, thus no way so far to use this method.
I'm trying to create a custom action, which seems to be working fine, but what I need to do is this action to use a custom api, is this possible at all with Payum?
So far I haven't been able to make this work without overwriting Stripe bundle.