How can I change the way Magento shows custom address attributes in the payment section?

I created a new custom address attribute with input type “dropdown” and filled it with options. When I create a new address and choose one of the dropdown options and go to the payment section my attribute is displayed like this:

Why does Magento use the attribute code and not the label? And why does it show the value “95577” and not the label of my option chosen?

Thank you!