[cncb]

But what is practically the problem?

If everything is fine but just that XBMC is telling you it runs in 1080p, it means that FTV is indeed running internally in 1080p at all time, and that setting the output to 720p does a downscale at the HDMI output level.

I assumed Windowed mode was doing some kind of extra scaling but if this is not the case then I guess there is no problem. Thanks.