An alternative solution is Isabella's "Shadow". It is simply a sheet run in the awning rail and supported by two or three grp uprights. Available in various lenghts; ours is 3.6 metres, and has three uprights.
It only takes a couple of minutes to put up or take down. We use it a great deal; often using it to replace a full or porch awning for the final night, if we need a "dry pack". Its dead easy to dry it latter with it just hanging from the rail at home, or you could put it on a clothes line.
A big plus for us is that it does not compromise using our other awnings as it leaves the awning rail free.
Thought I would seed you this alternative approach.