Problem solved! As noted, the rod is not "threaded." What appear to be threads are rings that allow the black lock ring to grip onto the rod. The rod is removed by holding the rod in the "out" position while pushing the yellow part to the "in" position. The "lock ring" becomes exposed, which exposes an open side to the lock ring. Then you simply push the rod sidways (rather than pull) out of the lock ring. Installation is reverse. Be sure to leave the lock assembly unscrewed so as to be able to position and install the rod. The last part of the procedure is reinstalling the 8mm lock screws to the trunk. Here's a link to the instructions:

http://mbca.cartama.net/showthread.php?p=154788#post154788