What documents are needed to apply for Chinese Visa in Bangkok for an American?

I am an American national working in Thailand and Singapore. I have and will be going to China for meetng conferences and exhibitions. My last multiple visit visa to China has just expired and I am in the process of applying for a new one in Bangkok. Besides my USA passport and Thailand work permit and work visa, the agent has come back to ask for ID card in USA which i provided yesterday. Today he is saying that I need to appear in person and also bring my bank passbook from Thailand... Can you tell me exactly what documents are required so that I can get this done efficiently? My main bank account is in Singapore, should I bring a statement from that bank? Thank you!