Jib backwinding main

Hi everybody. I'm from Brazil, this is my first question to the forum. Please excuse me my english.
Going upwind I've noticed that normaly as the wind increases ( over 12 KN) the jib begins backwinding the lower part of the mainsail around the mast. To conteract this, normaly I open up the jib traveler car a little. Doing this should I still use maximum jibsheet tension ? Or should I also use less tension ?
Some datas to my setup. I have the new pos 2002 jib and main is also new, the jib blocks are attached to the second hole from the bottom in light to medium winds and in the first hole in strong winds.
Any thoughts or suggestions on that ?

Many thanks
Tomas

Most Americans could learn from your English.

According to Gavin Colby (2002 World Champion and 2nd at 2004 World Championships), the jib car should be halfway out by 13Kts when beating upwind.

Max sheet tension is good and your jib block attachment sounds right assuming that you carry the jib tack in the lowest hole on the bridle chain plate (using a post 2002 jib).