Funny, I wasn't aware that Caravans could tow themselves around for more than 30,000 miles without requiring new tranny. Tow with one of those? No thanks.
Seriously, there's more to towing ability than horsepower and (especially) torque. Brakes, size of the tow vehicle, coolers (tranny and engine), and many other factors all are important.
Of course, it wouldn't surprise me to learn that the manufacturers cheat a little.
Folks here seem to be considering or trying to buy Eurovans. You may be better served by talking to the folks who already own Eurovans on the list at:
Those folks may be able to tell you how well you can tow with a Eurovan.
Personally, I would try not to tow unless it was significantly less than the rated towing capacity, by that I mean half or so. Most people forget that towing capacities are listed for empty vans, yet most people tow with a van full of family members, luggage, and vacation gear. Those oversized American butts seated in your vehicle further decrease your the amount of weight you can tow behind your vehicle.