I don't think that the VX is the best choice for your application. I regularly tow a 15 foot SeaDoo boat with mine with no problems, but ...

Towing that large of a 'box' behind the VX will probably cause the 'tail wagging the dog' syndrom. If you do this, make sure you have a good set of road tires that have good tracking characteristics.

I know that etlsport towed a fairly large U-Haul trailer with his with no problems so you may want to send him a PM to see if he can give you any tips.

I assume that your trailer has 'lectric brakes. Make sure you get that set up by a reputable person because our brakes are fine for regular use but prolly aren't enough for major towing. Upgrading to Stainless Steel brakelines would be a good investment as well.