How to unmask external bank account in R12

We're using R12 system (EBS R12.1.3).

to test the mask external bank accounts, I set the bank account to be masked in System Security Options.

Navigation is Payments Setup Administrator responsibility -> Oracle Payments Setup -> System Security Options -> (Link) go to task:

then setting Account Number of Bank account to Yes in 'Encryption of Payment Instrument Sensitive Data' section, set 'External Bank Account Masking Setting' to 'Display Last Digits', 'Number of Digits to Display' to 4 in 'Payment Instrument Masking' section. After applying the change, system automatically submitted the request set 'Mask Sensitive Data Request Set', After the request set completed, the bank acount number in customer site is masked.