The old awning should slide out of the rail to either the front or the rear. You will have to check to see how the old awning is secured into the rail. Sometimes a screw into the rail is used, sometimes the rail is pinched at the end.
The VTS stuff it awning is about half the cost of a new ZipDee, but alot more work every time you set it up. I put a new ZipDee on my trailer this year and could not be happier with it. I can set it up in about 3 minutes and most of that time is unlocking the hubs. I can roll it up (if the wind picks up) in less then a minute. I have a small step stool to help me reach the hubs and the awning rod to grab the loop. Installation was not hard and the instructions were easy to follow.
If the awning is wet when we pack up, I just unroll it at home for a short period to dry it out. I looked at the pros and cons of both awnings and went with the ZipDee.
Wally Byam Airstream Club 7513