Towing weight ?
First of all, don't accept that dry weight as gospal until you verify it on the scales. It may be right, if it really includes 'all options', but sometimes it is not accurate as additional options were added after the dry weight was listed. Second of all, that towing capacity of your van is probably for a van with no options, no cargo, no passangers, a 150 lb driver and a gallon of gas. You need to find what the actual weight of your van loaded for travel is (need the scales again). Then you subtract that weight from the stated GCVW (combined vehicle and trailer weight limit) to find out what you can REALLY tow.
Also, be aware that the trailer adds some weight to the van. You also need to make sure that this 'toungue weight' and the weight of the hitch/bar/etc do not cause you to exceed the GVWR or the maximum rear axel weight of the van.
It is better to look at the GVWR of a trailer when matching it with a tow vehicle. Dry weight is not always accurate, and does not include anything which makes the trailer usable, like Gary said.