Taking Ferry From Macau

I am American and will travel from the U.S. To Hong Kong for 4 days. I will take a ferry to Macau and go to Hensheng Island, sp be 1 night, then return to Macau for 1 night, then go back to Hong Kong. Can I apply for the 72 hour visa and where would I apply since I am not going directly from my flight, but from my ferry?

Thanks!