Proper way to reinforce Outback bumper for a generator rack

[Gilstan]

I have a 2010 Outback Sydney which already has a spare tire mounted to the bumper. In addition to the spare tire I want to mount a generator rack. All post I've read say not to do this without reinforcement. I looking for input on proper reinforcement. The generator and rack will weigh approximately 150 lbs.

[ktmracer]

On my outback (295RE), the bumper to frame mount is pretty stout, but the bumper is pretty flimzy. A local RV shop that has updated quite a few bumpers for higher carrying capacity took a look at mine and did there "standard" update. cut off the existing bumper tube, and replace it with a 4.5" square tube with 3/16" wall thickness and weld it to the existing mount along with gussets on each side. Welded a 2" reciever tube to the new bumper. Then they welded the spare tire carrier to the new bumper tube. Good enough to haul my 250lb dirt bike.