I am in agreement with Marmot & the Prof
However, like Marmot sez even if you beef up the hitch to the framework of the trailer it will not be a secure arrangement long term, or over rough or even bumpy freeways.
There is too much risk as well as liability when attaching something to the rear of your trailer.
At that rear point on the TT all movements are multiplied force.
Frame will not hold up.
Yes, you can put a camera back there but when something bad happens it is already too late.
Anything we want to haul, we put in the truck bed, behind the cab this is best for weight distribution. Generator, tools, bikes, gas, etc.. locked and secure.
If your tow vehicle is an SUV your options are more limited but there is always a way.
The worry, liability, and expense of something coming loose where I cant see it until too late is not a place I am willing to go.
The only thing on the back of our 189FBS is a PVC square tube that I keep our sewer drain hose in.
Just my opinions.