How change waveform scale to 0-100 IRE?

Question about scopes. How do I change the waveform scale to show 0 - 100 on the Y axis instead of 0 - 1023? I like to set exposure to IRE values. Thanks.
https://forum.blackmagicdesign.com/
https://forum.blackmagicdesign.com/viewtopic.php?f=21&t=137165