The person right above me has the right answer! It took me a long time to realize you have to press those two at the exact same time and hold for about 1-1.5 full seconds.
Also, for anyone interested i think i have figured out why the easier power/home button combo doesn't work here. I tried every combo of screenshot buttons out and they all work individually EXCEPT that the home button DOES NOT work when you are touching the screen. Just to make sure i tried it on my home screen and in other apps and it's the same thing.
For some reason HTC made it so the home button doesn't function while you are simultaneously touching the screen. I imagine they had some sort of good reason for this, but it just happened to mess with the one app that needs both
You can try it out and see for yourself.