First step is to make a strap out of the velcro strips. Basically, just stick the two strips back to back. Next, cut a 2 to 3 inch section of innertube and slip it over the jack handle. This will help keep it from rattling under the hood. Now you can use the velcro strap to tie the jack handle to the jack.

Next, cut another section of innertube (about the same size) and split it to lie flat. Use a tie wrap to tie it down over the positive battery terminal. This is mostly insurance so that if, for some reason the jack comes crashing down, it won't short out the battery, which would be a very bad thing.

Finally, drill holes in the large U-Bolts that the hitch pins will fit in. These should be about halfway down the threaded portion of the U-Bolt. Make sure that the holes are in a position that you can get the pins into them easily with the U-Bolt perpendicular to the support rod.

Ok, now the prep work is done, it's time to start on the actual mounting of the jack. Cut another couple of pieces of innertube, about 4 to 5 inches this time, and slit them lengthwise. Get the small U-Bolts ready with all the hardware close at hand. Put a tie wrap loosely around the support rod, then wrap the innertube around the support rod. The edge of the innertube should be about 4 to 5 inches from the firewall. Wrap the innertube fairly tightly, then use the tie wrap to hold it in place while you use the small U-Bolts to secure it permanently. Put one U-Bolt on each side of the innertube. These hold the innertube in place and keep the jack from sliding back and forth. Do the same thing for the rod on each side. The accompanying pictures show the general idea.

I have a 48" jack, the 60" won't fit under the hood. Turn the jack so the the flatter side of the head is to the top. With the jack underneath the support rails set one end on the fuse box and the other end on the top of the brake booster. I usually hook up the side above the battery first because the booster holds the other end up nicely. Feed the U-Bolt up through the holes in the jack and tie the jack to the support rail, securing it with the wing nuts. Look at the pictures, they explain it better than I can. Tighten the wing nuts enough that you can put the hitch pins through the U-Bolts.

It's really easier to do than explain, the pictures tell you most of what you need to know. This is admittedly not the most convenient place for the jack, and it does get a bit warm after a while on the trail. However, it does have the advantage of being out of the way and not taking up precious space in the tub. It's also fairly cheap and easy to do (I think I have all of about $10 into it). Oh, one detail I forgot, you have to remove the base from the jack, I store it under the driver's side seat.