I don't know a whole lot of detail about how kava is used for customary purposes in Vanuatu. Despite being mostly Christian nowadays, belief in sorcery is very strong. It's become integrated with newer beliefs introduced from overseas.
Some people say special kava is used to contact the spirts of people before they are born. Other rumors talk about special kava for reaching one's ancestors. This kind of knowledge is kept rather secret, either in exclusive graded societies or even restricted to one special person every generation who passes the secrets on down. There is a lot of variety, yet also some common themes. Alex François has some stories from northern Vanuatu here:
http://alex.francois.free.fr/AFtxt_select_e.htm
Remember, every
tok ples is different. Vanuatu has over 100 active local languages spread over 87 islands. When people get together for regional festivals in town, kastom dances tend to generate lots of interest. Lots of people are curious to see how other cultures do things differently. The ability to
posen or place curses across culture group boundaries is universally accepted. Just because that village over there, on that distant island does things differently, doesn't mean their magic is fake. This has led to some friction in town when one group accuses another group of causing bad things to happen.
Hmm.. other than that...
* If you are worried about weak or broken bones, you can have double bones installed in your body, according to a PCV who related the time someone generously offered double bones to her.
* Don't swim under any canoe that has a woman in it.
* Never leave your clothes drying outside overnight or you will become very ill.
* Never throw peanut shells in your yard. Dispose of them carefully.
* If you fall ill and don't know why, you may have been
posen. Seek the help of a
kleva, who may divine the location of small
nakaemas stones buried around the outside of your home.
Nakaemas is a type of harmful sorcery--
nakaemas stones are only one specific kind.