A few mates and me just bought one, we also bought a grab bag (just for the j mount), and a line mount. Word of warning the line mount works best with 4 line kites with the centre line y split low, eg cabrinha bars, etc. and is usless for 5 line high splits like the rebel. The line mount is quite lose so we run some split 4mm tubing over the line and the place the mount on that to minimise moving, and then cable tie to the cabrinha centre line swivel.
We made a centre strut mount by cutting two squares off the side of a 2L thickened cream tub (polyprop so strong and flexible)
-Stick the two squares together using double sided tape.
-Drill and Bolt a curved base to the two plastic squares, make sure bolts are on the underside (so kiteside), and use a dremmel to cut off the excess nut thread (slowly and carefully, too fast and the heat will make the plasic melt)
-Cover the bolt heads with a small piece of 4mm self adhesive foam (clark rubber, we had a piece lying around) this will protect the strut and stops it moving.
-We then used the dremmel to rout out two slits about 1.5 cm from the edge, this holds the velcro stap and buckle to attach round the kite.
-we then used the dremmel to take off all the rough edges
-then use the j mount to shoot images down the kite.
all of the bits we found lying round my mates shed, and it took an hour to make, not pretty but does the job. the mount has gone to exmouth so we can take photos and video during expo week, but i'll take photos and add to this post on friday, so you'll have to make do with diagram until then.