Don't know about your country of residence, but some countries have technical document which is used when selling/buying car, and recording any changes etc. It might have the details you need there.
If we check on here, and use hiace as reference, as they related, you can see towing capacity in case the caravan has it's own braking system is 1400 kgs for all models.
https://towingcapacity.org/toyota/hiace/1996/
Seeing as yours is 2wd, i would not push my luck.