I apologize that your question has not been answered yet. I think that your question is important, so by my answering here now, it will help to move your question more to the top of the list of questions that need to be answered.
I don't know about the short shag haircut. But, you might find some information on the following sites that will be helpful to you. I hope that you do. Maybe someone will come along who knows the specifics concerning cutting in the style about which you are inquiring.
How to Cut Hair | eHow.com How to Do Hair - LoveToKnow Hair How to Cut Hair