Whether VOA applicable to travel China With Official Passport?

I am Sri lankan, working at Ministry of Sports in Sri Lanka as Chief Accountant. I hope to travel China for Official duty from 20th August to 26th August 2013.( It is for Nanjing, Closing Ceremony of 2nd Asian Youth Games) I have an Official Passport. When I apply, Your embassy official told that visa is not required to me as I have a Official Passport and VOA will be given on my arrival in Shanghai. So, I want to get it confirmed, Whether I will be allowed to travel China By Sri Lankan Immigration and China Officials at Shanghai. I have a cofirmation letter of Invitation issued from Nanging Youth Olimpic Games Organising Committee. Your early response is highly appreciated.