NEED HELP WITH THE STUDENT FINANCE 2011 UK?

In the application for the student finance (I am italian) there is written that I should bring a copy of a document and make sure that it signed by a officer, doctor, lawyer, pastor/priest,.. Which document should I bring ?? A photocopy of my id ?? Or a photocopy of my passport ?? And what should they do ?? Just sign it, or write a letter ?? Thanks.