It is a simple matter to give a child a gun, drug him up to the eyeballs and tell him to kill your enemies. But Father Henry de Penfentenyo, a Roman Catholic priest who runs a youth centre in the rebel-held north of Cote d'Ivoire, says it takes his large team of carers several weeks, and usually several months, to rehabilitate each one to the point where he or she can be sent back home safely.