Currently (until 2009 or 10) you may get through ok by showing a Canadian Drivers Licence and possibly your Social Security Card. You likely sent in your old pp in the renewal process, but if you still have it this might help also.
Hopefully they don't send you 'inside' for processing, as this can mean a lengthy delay to sort things out.
I don't think the mandatory showing of a pp comes into effect until next year.