The dual role performed by the mortgage broker, or a mortgage banker or an exempt entity acting as a mortgage broker, in those instances when the mortgage broker is also the real estate broker in the same residential real estate transaction, must be disclosed at the first substantive contact between the mortgage broker and the buyer/borrower. In addition, any regular business relationship that the mortgage broker maintains with any lender to which he/she presents loan applications, if he/she intends to utilize three or fewer lenders, must also be disclosed at the first substantive contact between the mortgage broker and the buyer/borrower. The appropriate disclosure form and acknowledgment set forth hereunder must be provided to and signed by the buyer/borrower and the seller before services as a mortgage broker may be rendered. The disclosures required by this section may be in writing or via electronic transmission and the required signatures may be hand-written or digital to the extent such signatures are recognized as binding under New York State law. A hard or electronic copy of the disclosure form and signed acknowledgment must be maintained by the mortgage broker for at least three years.