hi about china visa in hong kong

I have ticket from Kunming to hong kong (march 3) and then return ticket from kunming to India (31st march) back. i wish to apply Chinese entry permit in Hong Kong (between march 3-6) and then go to china till march 31st. Is it possible to apply chinese entry permit in hong kong or should i get it before hand? I can stay in Hong Kong with pre-registered online entry permit for 14 days .