Wishful thinking I'm afraid, HDAVI facilitates control of multiple home cinema (and similar) audio and video components, input selection and activation, with the touch of a single button on a remote. HDAVI control is implemented with CEC (Consumer Electronics Control) which is part of the HDMI standard.
After churning out silver, silver & more silver Panasonic seem to be having a black phase now
Instruction manual can be downloaded from the UK website. It's a universal manual so you have to watch out as some stuff might not be applicable to UK/Europe.
I read several user reviews from an american forum on this forum ,and if I remember rightly the main difference between the s52 and the s53 was the 1080p upscaling .Also the newer s53 received some criticism because dvd-audio had been dropped and also the ability to alter the brightness,contrast,colour,sharpness and gamma settings.I have the s52 and found the preset picture settings not very good but after playing with the personal settings managed to get a pleasing picture to my eyes .I think the thread was under Panasonic s53 but not sure,maybe worth checking out before you purchase .