how do you reset the maintenance message?? on 2008 Volvo S80

I use a local mechanic to service the volvo, and he could not reset the message to have car services. I called the dealer, and they wouldn't tell me. Must bring car into the dealer.

Asked by for the 2008 Volvo S80
press you start/stop button once without your foot on the brake pedal. press and trip button until T1 is displayed. then press and hold that button again. the dash lights will come on and some lights will flash. when this happens release the trip button. thats it
I have a 2010 S80. The responses to the procedure you outlined, but I get a "163" message after the beep and it still says service overdue when I start the car up??