[quote name='jmcc']Resign yourself to either using a stand for it, moving it to one of the other walls in the room (one of them has to be load bearing I'd think) or tearing out the existing wall, putting studs in, and re-plastering.[/QUOTE]
I think jmcc's hit it on the money here. Unfortunately with the size of that TV you'll have to anchor it to something, which apparently there's nothing to do that. With a much, much smaller TV and depending on the thickness you could try some kind hollow wall anchors, but no way that'll hold a TV of that size.
I'd say simply purchase a stand for it. They make some that are very streamlined and designed to appear small and out of the way. There's even some that "simulate" a wall-mounted style I guess you'd say, but in my experience every one fo those seems to make the tilt one way or another after a little time.