Problem with electronic trasmission - sth is wrong with the reverse, GEARBOX

Hi everybody. I've got Kia Carnival - the big suv... the trasmission doesn't work, reverse mainly. I could not find anybody able to help me (local dealer know even less that me), so I have to fix it myself. DOES ANYBODY HAVE TECHNICAL DESCTIPTION, DRAWINGS, ETC. TO KIA ELECTRONIC GEARBOX ? THANX A LOT.