RHD through Cameroon and carnet
 

RHD in Cameroon & Carnet after Gabon

Hey - does anyone know how strictly the law is enforced regarding RHD vehicles in Cameroon.
Is it possible to enter the country and cross it in a RHD since the new law in 2008 or is a LHD the only way to go - I have a RHD already in West Africa and wanted to take it south if possible.
Also as a seperate question - when does a 'Carnet' become an absolute neccesity??...been as far as Gabon without one before but no further.......
Any advice appreciated
Thanks