Custom Fields & Fulfillment Jobs

I have a custom Contact Tab with many custom fields. I want to create a Fulfillment Job which will export both default and custom fields. When I test the Fulfillment Job, only the default fields export any data. The CSV file contains all of the fields but only the default fields contain any data. I see that my custom fields in the Fulfillment Job dropdown lists show up multiple times as, eg, Contact.BankName, Daughter.BankName, etc. I have tried a custom field using each of the alternatives. None have worked so far. How can I find the right custom field to use when exporting?