The towing capacities seem to be a regional thing. Here in the UK they are much higher for the Track/Kick (2543lbs braked/1653lbs unbraked). Those figures may be based on what the UK legislation allows -1653lbs/750kg is the legal max for an unbraked trailer. I've towed a car trailer with an SJ on it and it managed OK, lots of use of the lower gears on hills though.
I don't have all the figures for my 413 pick up but its max. towing capacity is stated at 2420lbs. Its an lwb so therefore should be a bit more stable, but I reckon the 1.3 would really struggle to pull anything like that figure.
That tow dolly, was that 3000lbs loaded or a tow dolly with a 3000lbs max. capability?
Even with a braked trailer I found that the Vits braking system was working harder than I'd like.