Thanks for the reply, I have a wind out omnistor awning, but it is not that I am referring to. Over the joint all the way round the seems where the side meet the top/bottom of the motorhome there is an aluminium trim that has a channel (just like an awning rail) at one point two pieces meet at 90° with the cover that has perished. I only described it as an awning rail as its the only description that really fits. I have seen a similar channel on caravans. You couldn't use it as the 90° corner would stop any awning fed into the channel.