The Xenon mast comes ready fitted with holes for the trapeze kit. The kit is available as an accessory from Topper (approx £132 in 2009) although all component parts are readily available if you wish to assemble your own. If you purchase the trapeze kit from Topper it will come with all the bits you need except installation instructions!! The task is simple and straightforward and positioning is not critical although the length of this guidance may lead you to believe otherwise! I hope it helps.
First insert the 'T' ends of the trapeze wire into the mast holes. Mine were a tight fit and had to be wriggled to get them to bed in properly to the mast openings. Rig the mast complete with upper and lower shrouds.
The next task is to install the bungee line that holds the trapeze wire ready for use. The ideal is to have a sufficient length of bungee line to enable the trapeze wire to be fully and easily extended when hiking but capable of returning the wire and its handle to a convenient resting point when released. The means of achieving the length needed is to lead the bungee cord from one trapeze fastening to the other via the bow of the dinghy. There are several options for doing this. One method is to simply loop the bungee cord over the furler unit. I noted that Topper had used this method when displaying a Xenon at the London Boat Show. However this approach has the disadvantage that the bungee cord can get in the way or caught up with the gennaker lines, painter, furling line etc it also looks a bit amateur. After a little exploring I noted a deck eye deep in the bow of the dinghy, just above the bowsprit, used to fasten the leading edge of the gennaker chute. There is plenty of additional room in this deck eye to allow the free movement of a thin bungee cord. It has the twin advantages of providing the maximum length (and therefore extensibility) of bungee cord and importantly the bungee cord is positioned well clear of the gennaker lines and runs neatly along the side of the chute, under the mast bridge and on to each gunwhale. I adopted this latter method and it has worked well.
The next stage is to fasten the two small deck eyes, provided with the kit. These are positioned on the inner sides of the gunwhale such that the trapeze wires are as close to the shroud lines as possible, ie out of the way when the trapeze is not in use, but not so close to those lines to tangle with them or to prevent a quick and easy grab for the trapeze handle during a tacking manoeuvre. The position is not critical but as a guide I have found a position 120mm to the rear of the main shroud fastening and 80mm down from the top of the gunwhale to be suitable. Mark the position using a washable marker. Now loosely tie the ends of the bungee cord to the small loop in the trapeze rings. Using your finger as a temporary deck eye place your finger on the marked position. Check how the trapeze handle hangs, you may need to shorten the bungee line to get some tension but do not cut it at this stage. Move your finger around to find the most convenient hanging position of the trapeze handle and make a final marking on the gunwhale. The deck eye is fastened to the inner side of the gunwhale with two self tapping screws. These can be forced in but using a fine 1.5mm drill bit to drill a pilot hole, then inserting the first screw will give a much better result. Angle the deck eye at 45 degrees towards the bow and using the deck eye as a template drill the second pilot hole. Fit the final screw. You will need to release the bungee cord from the trapeze ring, pass the end through the deck eye and finally tie off back onto the trapeze ring using a stopper knot at this stage. Repeat this procedure for the other side of the dinghy.
The final task is to get the right bungee tension which is not critical. You should aim for the least possible tension in the bungee cord consistent with the trapeze handle being held in the correct position and not blowing around in the wind. The trapeze ring is height adjustable and therefore set the height to its normal operating position, say 250mm below the cleat, before you start the tension adjustment. I suggest that you experiment by shortening the length of the bungee cord, temporarily tie it off, check that the bungee cord is evenly tensioned around the bow deck eye and when satisfied that the trapeze fittings are not flopping around cut away the excess length of bungee cord and finally tie off.
One further point - if you are in the habit of completely derigging your dinghy after sailing you will now have permanently attached your mast to the dinghy by the bungee cord! I have solved this problem by using two small, eyed, carbine hooks on the ends of the bungee cord. In use the carbine hooks are attached to the bungee fastenings in the trapeze rings and when not in use the carbine hooks are stretched forwards over the mast bridge and clipped to the bungee cord keeping the cord in gentle tension and out of the way.

Nothing to do with maintenance but you will of course need to obtain a trapeze harness. These vary in price from around £80 - £150. As 3 of us frequently sail in our Xenon with only a single trapeze we required a harness that would fit all of us. In the end we settled on the T1 Zhik adjustable Velcro harness. This is easily adjustable to fit many shapes and sizes although it has the minor disadvantage of being a little more bulky than a tailor made canvas harness. It is however secure and comfortable to wear.