transit visa for afgan national

dear Sir,
i am faizal from orient travel ,sharjah ,uae and i have issued a ticket for an afgan national MUHAMAD/ALIMR who is having a long term visa to japan who is in kabul at the moment to travel to narita via GUANGZHOU from dubai on china southern airlines on the 18th april 12.Transit duraion is around 19 hours and overnight and the airlines is insisting for a transit visa,please adivse the transit visa fee and how long it will take after applying to obtain.