Due to various organizational reasons, it is not possible to determine the actual payment method during checkout. I need empty payment method, which just says you'll be informed within a hour.
Easiest way: Magento comes with a payment method called 'Check / Money order'. Just edit the title of that method and use it as an 'empty payment'. Check the
system->configuration->payment methods section.
As Marius sayed, it the check payment is a very simple, almost empty one.
If check payment might still needed in additional as another payment method in the future, it is quite easy to create an own payment that is derived from the 'check / money order' payment, but this would need some coding.