Data field employee id mapping for centrally billed Mastecard CDF3

Summary:

We are moving ahead with the MasterCard Centrally Billed Travel cards where the bank informed us that the employee ID will be mapped in the system via an enhanced data mapping functionality .In this the employee id will be passed on in the file as the data field instead of employee id tag in the Mastercard cdf file

We want to understand how are these data fields processed in the oracle system and in which record type should these data field be exactly tagged to for the system to read the employee id and map it against each transaction