Michael Schumacher could keep on competing in the annual Race of Champions, to be held in Bangkok in December, 2012, for at least a year after he retires from Formula 1.The seven-time World champion has won the Nations Cup event in partnership with Red Bull's Sebastian Vettel, currently chasing his third successive world title, for the past five years.VETTEL AND SCHUMIThe two Germans will pair up again at the Rajamangala soccer stadium on December 14-16 to try and win the event for the sixth time in a row and Schumacher, now 43, said it would not be his last appearance.Schumacher said: "I'm looking forward to racing with my old mate Sebastian for another repeat of our title."But my lucky number is actually number seven. So we've got to do this and then the one after. That would be the ultimate. Obviously this means I'm not retiring from the Race of Champions yet," added the Mercedes driver."I could have retired from it by the end of this year, but I don't want to. It's too much fun. And as long as I'm still a bit competitive in it, why not?"LUCKY NUMBER 7Vettel, who leads Ferrari's Fernando Alonso by 10 points in the F1 championship with two races remaining, including the 2012 U.S. GP in Austin, Texas, looked forward to continuing his partnership with Schumacher.Vettel said: "I think Michael will stick with me in the future because we've got to get at least seven. It's a lucky number for him, so that's the big number we have to achieve.The Race of Champions features winners from various motorsport series competing in identical cars.