How does the official Kassa Compleet extension for Magento 1.x handle the «Bank Transfer» payment option?

Preliminary reading:

1. ING_PSP_Block_Payment_Banktransfer_Info::_construct()

2. ing_psp/info/banktransfer.phtml

3. ING_PSP_Block_Payment_Banktransfer_Info::getMailingAddress()

4. ING_PSP_Block_Payment_Banktransfer_Info::_convertAdditionalData()

5. ING_PSP_BanktransferController::paymentAction()

6. ING_PSP_Model_Banktransfer::getMailingAddress()

7. etc/config.xml