How to buy train ticket if passport is needed now as of 1 June 2011 ?

Learnt from China friends that in order to buy train tickets from shanghai to Beijing, identifications eg passport are needed now. How can we as tourists buy these tickets then if we need the train ticket on the day when our flights reach shanghai and taking the train from SHanghai to Beijing in the evening? Will booking from your site work for us? We need D train tickets D308 from Shanghai to Beijing on the 7th June evening. Reaching SHanghai in the afternoon of 7th June. How does the system works now?