A bit late now I admit, but one of the many advantages of a folding bike is that you can generally fold it up and take it with you into a building. Taking off any easily removed parts such as seatpost, lights, computer and pedals (if MKS Q/D pedals) is the next best option.
Otherwise perhaps, fold it up before locking it to something solid with the best lock you can afford.
Last edited by simsles; 07-10-08 at 08:17 AM.