Last time I had anything to do with jumping from a helicopter, the aircraft had to have a supplement in the Flight manual detailing any necessary mods, the pilot had to be approved by the BPA & tested by a BPA examiner and the helicopter's operating company had to have an approved section in their Operations Manual detailing the training required and the Supplementary Line Check.
I can recall doing a pilot's checkout as a BPA examiner, signing the supplementary line check form as the company line check captain and then diving over the side. Not awfully comfortable as it takes longer to reach free fall velocity and proper control.