The following instructions are from www.solsticeforum.com

http://www.solsticeforum.com/forum/f62/how-customize-seats-inflatable-lumbar-support-53766/

If you are like me (lower back problems from time to time) , I wanted additional support in the lumbar area of our seats. I found a very inexpensive solution that has really improved the riding comfort. An adjustable inflatable lumbar air bag can easily be installed in the seat back by anyone capable of minor dyi skills. This unit can be purchased at Universal Inflatable In Seat Lumbar Air Bladder.

First, fold the seat back forward and pull out the seat back zipper that is tucked between the seat back and seat to get access to the zipper on both sides of the seat.

If you use a small screwdriver that fits in the hole of the zipper slider and hold the lower ends of the zipper, it becomes easer to unzip.

Unzip both sides of the seat back and lift up the cover which will expose the support frame and the seat foam.

You will need to provide a metal support plate from light sheet metal about 5.5 x 10 inches and slide it between the seat foam and back support. Mark the area and drill holes to use nylon ties to attach the support plate to the frame.

Use a light coat of contact spray adhesive on both the backing plate and air bag, allow to "tack up" and position the air bag on the plate.

Slide nylon ties thru the previously drilled holes and attach the assembly to the seat frame with the air bag between the seat foam and the backing plate.

Zip up the zippers and feed the squeeze bulb between the seat back and seat bottom. I wanted the bulb on the inside, but it's your choice. It has really made the seat more comfortable on long trips.