HDRP, how to get enums to post processing effect UI.

How can I assign an enum to post-processing UI in HDRP? (I’m using Unity 2019.3b8)

With Post-processing Stack v2 that was possible with some ParameterOverride or something like that, but I haven’t yet found similar command. Enums didn’t seem to appear to the UI when I tried it by just adding an existing enum I would have wanted to use as a selection for certain post effect features.

I’ve been going through API docs and the available code for a few hours and haven’t found a solution yet.
Looks like there are some pre-built parameters for bloom (BloomResolutionParameter) and a few other things, but what about a custom? Any pointers to right direction would be appreciated.

Just in case it’s unclear what I meant, pop-ups that exist in the built-in post-processing effects:
That Mode box that says ACES and reveals a pop-up with options. It was earlier possible to create own enums with Post-processing Stack v2.

5134277--507863--tonemapping_as_example.PNG