This is all I could get on carnet, FBR don't have even a single word on the website. This is taken from a traveller's diary.
aCarnet de Passages
[/url]To enter Asian and African countries with your own vehicle a Carnet de Passage is required. It is a document to ensure that you export the vehicle again after you have imported it. Without a Carnet you will have to pay the import tax, commonly a few times the value of the car, at the border on arrival. You'd better get a Carnet!
A Carnet de Passage is issued by the motoring organisation ("AA") of your country. In The Netherlands you have to contact the "Afdeling Grensdocumenten" of the ANWB. Of course a booklet and a few stamps only will not keep people from selling their vehicle. Therefore you will have to lodge a deposit or bank guarantee to secure the Carnet. The amount used to be approximately the original selling price of the car in the year of build. Fortunately, by using an insurance construction the ANWB was able to lower the amount for the deposit or bank guarantee. The required bank guarantee is now about 1.5 times the actual value of the vehicle. The price of the Carnet itself is a few hunderd euros.
You will loose your deposit or bank guarantee when you have an incomplete set of "in" and "out" stamps, and you can not prove the car was destroyed or stolen. Especially the latter will face you with a lot of bureaucracy. But when your car is stolen, you are in big trouble anyway...
Even with a Carnet your car is only allowed for a limited period in a country duty free. For India the maximum stay within 365 days is 180 days. Do not exceed the 180 day period because they will check for it at the border and even a one day overstay can result in fine surpassing the value of your car! In Pakistan the maximum stay is 3 months but this can be extended via some bureaucracy at the Revenue Department, Constitution Avenue, Islamabad. Generally the Pakistani custom officers tend to be more relaxed and helpful than the Indian ones.
Here are some links (seems very old).
http://www.cbr.gov.pk/newcu/sros/1979sro974cu.htm
http://www.cbr.gov.pk/newcu/sros/1998sro1339cu.htm