Guess I have to call the dealer tomorrow and ask what this is all about. If the car needs service every 7500 km, then this will turn out to be an expensive car to own!
Update: The last two months I have almost stopped using the 6. gear and have driven with a higher rpm. And I have also done more hard accelerations. And the service message has stopped coming! When I talked to the Saab technician and booked time to do a engine software upgrade, he told me that the service message could turn up due to the engine sensing soot. And he told me to do some hard acceleration to blow soot out of the engine and particulate filter. And so he gave me an explanation to why the service message has stopped coming. I guess the moral is that I was the sissy. But now I drive my car like a man! :)
Update 2: Yesterday my dealer updated the engine software on my car. Evidently the car had sensed soot and flashed a premature "Time for service". With this update the engine will stop flashing "Time for service" since this soot do not pose any danger to the car. But as you can read from my first update, the service message stopped coming when I started driving my car like I should have from the start! :)