There are many ways to reduce weight in your carry-on if they weigh it at the counter. For example:

- Load heavier items like iPod, phone, camera into all your pockets
- Wear any clothing that you have in your carry-on
- If travelling with someone else, check in separately and have them look after a few of your heavy items eg. laptop and then swap when they check in
- In smaller airports I have even taken my laptop out of the bag, put it under a seat by the check-in desk and then checked in without it in my bag
- At a rural airport I also left some items hidden in the bushes outside!
- If you drive a car to the airport, leave your laptop/heavy items in the car and then go back to collect them afterwards
- If you have lounge access (for AirAsia this would be the small landside lounge at KUL LCCT) you can check into the lounge and leave your bag with the attendant for a few moments while checking in
- Charm the check-in person. If you know there's no other way to remove the weight you can admit you think it's too heavy before they weigh it and usually they'll be nicer about it

Good luck!