Stereoscopic Player + Bluray (SSIF files) = No full screen!

[Louarias]

I have SSIF files from my blu ray back up which I have played with stereoscopic player but I cannot seem to use the full screen of my 3dtv but only a limited widescreen - cut top and bottom but still seeing the whole movie picture (I hope thats clear). I have played around with the customise aspect ratio option but still no joy. I have used powerdvd but that has the same (tru theatre option greyed out). Can someone please help? Its rather quite annoying having a large tv with only 65% of it is being used.Thanks