Answer:
The best course of action is to contact the card-issuing bank, which also has the reporting obligation once you inform it of the facts. That bank has the information needed to complete the filing. You can then annotate your records to indicate whom you called and can even ask them to provide you a copy of the CTR for your records.
You'll find justification for this approach, I believe, in FinCEN Ruling 2001-1.
First published on BankersOnline.com 11/22/10