I don't recall ever seeing an off-the-shelf solution for carrying a generator like that, but I've seen it done many times so I know it can be done. While I'm sure the naysayers mean well, they are mistaken. It can be done safely and securely on any RV. It's all a matter how it's executed.
Reddog1 has a simple but very functional setup for his Honda 2000 and I believe a gas tank hanging on his ladder. A few other members have started with either a "Hitch-Haul" type cargo rack or a steel utility box like you might see under a flat bed truck, and modified it for carrying their generator. The contraption I have on the front of my truck started out as a truck bed toolbox, and I've spent an insane amount of money and time turning it into what you see today. I carry a Webber baby Q grill and a Yamaha 1000 generator in it.
The simplest mount for yours could be just a flat piece of steel with a few strategically placed holes for mounting to the bumper, and securing the generator to it. You probably should give some thought to the security of the generator hauling it like that, but they make these things called "chains" "cables" and "locks" to help prevent theft. If you put it in a box and intend to run it inside the box, you have to consider the cooling needs of the generator. Even if you run it out in the open sitting on a bumper mount, you have to think about where the exhaust is going and whether is presents a danger to you inside the camper.
:):)