Standard Def Waveform Vector on HD

I shoot HD with the new Panasonic AJ-HDX900. This camera will give you Standard Def SDI and Standard Def out of video out. I have heard you can use a standard def waveform/vectorscope to set up an HD camera. What I was told that the Gamma setting will be different on the waveform because you set up HD black at zero and SD at 7.5. So when I have a greyscale chart up and want to set my blacks, master ped etc. Is zero on a standard def waveforn from an HD camera zero? Any other tips on using a standard def waveform/vectorscope? And please don't tell me to suck it up and always use thge Leader LV5750 clients won't always spring for the rental.