I think you can mail them notary copy of your green card.That's what I got from the website of Chinese Consulate at New York. Better not to send them the original one. You don't know what's going to happen there. Just don't trust these guys.

Check this link:

http://www.nyconsulate.prchina.org/chn/lszj/bzyq/hzqz/t42306.htm