Records.

Records. Consistent with 501.601 and 501.602 of this chapter, U.S. persons who receive payments pursuant to paragraph (a) of this section must retain for ten years from the date of the relevant payment, and furnish to OFAC on demand, a record that specifies the following for each payment:
(1) The individual or entity from whom the funds originated and the amount of funds received; and
(2) If applicable:
(i) The names of any individuals or entities providing related services to the U.S. person receiving payment in connection with authorized legal services, such as private investigators or expert witnesses;
(ii) A general description of the services provided; and
(iii) The amount of funds paid in connection with such services.

Source

31 CFR § 558.508

Scoping language

Professional fees and incurred expenses.
(1) Receipt of payment of professional fees and reimbursement of incurred expenses for the provision of legal services authorized pursuant to § 558.507(a) to or on behalf of any person whose property and interests in property are blocked pursuant to § 558.201, is authorized from funds originating outside the United States, provided that the funds do not originate from:
(i) A source within the United States;
(ii) Any source, wherever located, within the possession or control of a U.S. person; or
(iii) Any individual or entity, other than the person on whose behalf the legal services authorized pursuant to § 558.507(a) are to be provided, whose property and interests in property are blocked pursuant to any part of this chapter or any Executive order or statute.
(2) Nothing in this paragraph (a) authorizes payments for legal services using funds in which any other person whose property and interests in property are blocked pursuant to § 558.201, any other part of this chapter, or any Executive order or statute has an interest.