I fought this same thing last weekend after changing out a trampoline. Bring your boat to Availa for the North Americans and I'll help you with it.
If you do not want to make the drive them maybe this photo will help. There should be no bolts going into the crossbars. There should be a length of thread all with an allan wrench hole in one end. It goes through the reinforcement plate riveted to the crossbar and screws into a bar that slides inside the crossbar tramp track. Note the bar in the photo below is from the Starboard rear position it about an inch longer than the others three. Also be aware at some point Hobie changed from coarse thread to fine thread, be sure to match up correctly. My 91SX has coarse thread.

Good luck,