If you have a need to mount a screen away from the wall the best thing you can do is go to B&Q and buy a bracket exactly the size you need it that will match the decor of your room. The Draper one is anything but pretty:
and is really intended as a keystone eliminator for schools and colleges etc.
All you need your bracket to do is screw to the wall, have an arm long enough to clear your curtains etc and have a small hole at the end with an S-Hook or something to join to the screen casing. Then as suggested fit a pelmet around it or something to hide it (or you could get really adventurous and panel out a portion of ceiling to hide the whole lot!)