How can I attach net curtains to PVC Double glazed bay window?

I would question who told you that hooks cannot be screwed into your window frames. I am looking at ours held up by tension wire and screwd in hooks! I used a 1 or 2mm drill to make a small hole and then screwed them in. Obviouly you can't drill near the edge of the frame where the glass is recessed in but there is plenty of room above the "glass" line up in the corners!  more