I was referred to this thread by DonnaD (of course) in another thread. My Burro
had instructions involving a combination of the aluminum window frame and short screws through the inner shell (only) to hang curtain rod brackets. Less work were some little hooks that a previous owner attached with short screws to the inner shell that took stretchy curtain cords instead of rods. I haven't put all of that back together yet, but now I have a couple of options to work with. Of course just gluing the rod brackets up with fiberglass epoxy is another option.