Couldn't find a good picture. But, on your signature pic (trailer 1), according to what I was told the rafter is the bar that follows the awning fabric on the side from the trailer to the roller that the awning is attached to. Fun trying to explain....when you unroll your awning, it is the bar you attach to the awning before you raise it. I believe when the awning is retracted it hangs freely Behind the other arm that you raise the awning with. The half peices I have now are are attached to the trailer and hang freely behind that arm. I have contacted Marksrv.com and they said that I had the old style and they changed the tubes(to exact opposite of the old style).They told me I could upgrade to the new style, but they only carried one of the 2 pieces. Sorry to ramble, not quite sure how to explain. Here is a link to marksrv http://www.marksrv.com/ultrahardware.htm
Go down to where it says hardware changes and maybe that will explain.
Thanks for answering!