2003 Ralf and rom question

Just downloaded a few videos where Ralf does a C, dp+A/C, and cancels into a hcb+D. Looked quite nice so I tried to do it. But out of 100 times, I've only managed to do it once!. And at that single time I was the mashing the D-Pad in all directions!

How do you set the HP bar to infinite when playing in practice mode in the rom console setting?

I don't know the answer to the question you asked as I use the home version. One comment I'd like to make though... the combo is just as difficult to perform on the home version as you have described. If you practice for a day or two you can get up to anywhere from 20 to 50% consistency at times, but I think that 100% consistency is impossible.