I think the Vito has a very low weight tow capability?

Your van will have a plate on it that states the max braked or un-braked train weight, which is the trailor, the car thats on the trailor and the vans weight.

For example, my Connect LWB has a gross train weight of 3200kgs iirc, and the vans gross weight is 2200kgs, which leaves 800kg braked.

Most trailors are around 500kg, so that would leave me 300kg of 'cargo' to put on the trailor