I welded hooks on my bucket, we pull up to the front of the trailer connect the chain to two of the hooks and on each side of the trailer, then back up a bit to tighten the chain.
On the back I have a clevis on the drawbar, chain thru that, then we use a lever chain tightener.
It seems to work pretty good.
Here are some pics of how I tie down the L3800 with the mower on the back and FEL on the front. You would do something similar with the BH on the back. Just lower the boom to the deck run the chain over the top of the boom.
Make sure you pass the chain under the pistons on the FEL. If you run in over the pistons you could damage them.
Remember to adjust the break-controller on your trailer. I have to readjust mine depending on if it empty or loaded.
Here are some more.
Sorry guys, but that setup is not safe, or legal for quite a few reasons. If your hauling commercially your bound to get a ticket from Mr. DOT officer.