Awning Still leaking

[Hettys Hommies]

Well there I was thinking I cured the leaking awning, but to no avail. I have a Thule Omnistor awning on the moho, this is a bit shy of 5mtrs, our Dometic ace air pro 500s awning is a tad bigger than the Thule, the dometic isn't 500 as stated. The fixing for the Thule to the moho is shorter by around 100mm to the end of the Thule so water can run between the gap. I have had to pull the awning further out of the track to the rear of the moho so we can still use the garage, otherwise the side of the awning sits over the door stopping us from using it. I was hoping with a plastic bag stuck to the roof and covering the gap would work but it clearly doesn't, has anyone got any ideas how to do it so we can still use garage door, even if the awning is pulled over door there is still a overhang on the ends. I guess I could buy a longer Thule but wandered if there are extension pieces you can buy to cure this. I bought the awning from Cannock Caravan Accessories, the guy did say he has to say don't buy it as a sales man but of record he has known people to do what I've done and it's worked fine, any advise would be greatly appreciated. Tia
John .