I think the hardest part would be finding the diesel-specific information, as I've not heard of anyone bringing a 3.1 into the country, automatic or manual.

You might want to check on some forums in Australia or New Zealand (I recommend Club Isuzu in NZ; Outer Limits is another good one) to see if anyone can get you this information, as they have these engines available to them locally.

Judging from what I've seen with regard to Isuzu parts interchangeability, if you can get the Toyota box to bolt to the Isuzu gas bellhousing that's probably proof enough that it would work with the diesel, too.