Change default Zip/Postal Code from "0"

[nrcjea001]

Hi

The Zip code is not relevant in my country and it is better that I disable it as an address field. However, some banks require a zip code in order for credit card payments to work. When the zip code is disabled the default value is set to "0" and is therefore rejected by the bank. I wish to change this default value. Whenever a guest or customer makes a payment, the zip code should be automatically assigned a valid zip code. 

Any ideas?