Zitat
were do you get the fabric?
Ebay, see this topic
Templates for Window Sunshades. (3)
Zitat
Maybe sides could also be made as the caravanstore has side struts, doesn't it?
Yes it does, but my one at least didn't have a slot in them ....the front rail (the one it rolls up around) has a slot that takes 4 mm awning piping (as opposed to 6mm awning piping that fits the awning rail)
So I was able to sew 4 mm awning piping along the top edge and nylon strapping along the lower edge (the type used for rucksacks) and sew in some loops for bungee cord.