The answer is Yes you can do it but it requires quite a bit of work, widening the transmission tunnel and other fabrication etc. Earlier vitaras had quite a simple auto (o3-72LE) that has no electrics to piss around with that you can use.
you need to modify the vitara gearbox to mate up to an sj tbox as well.
have a read
here (uses a kit available in the US though)
and here is Baloos take on fitting a vit auto into an SJ; I'm not even sure if baloo ever got it finished though????
remove vit transfer case from gearbox
remove all the black bolts from the tcase to take of the front section
pull this bearing and shaft out and replace with a bearing of the same outer diameter (72mm) but with a smaller internal diameter (32mm I think)
you also need to swap the oil seal for one that fits the sj to transfer box prop.
make a blanking plate out of 4mm steel/ally
You'll need to shorten the intermediate prop as well as modify the gearbox crossmember to sit the gearbox lower.
If it was me I would raise the tbox to help line it all up and to give you a flat bottom