Just FYI for guys this is a very easy fix! What I did when building my bumper is took the washer from the inside of the frame mounts. welded on some strap metal and made the hole to keep it in place. Now I had to bend it to make it fit right but a piece of cardboard is your friend to get it right. Paint it due to very little stuff will hit it so it won't rust and if you have a powdercoat handy do it. Sorry I don't have good pics of it due to didn't think people would care but here it is. I was kind of under the impression all the aftermarket bumpers came with it to support the lower trim.
Pics you can see the black flat strap of metal going up to it.
Use the inside upper bolt/washers.
You can see it if you look hard here too
And the other side