Adding heightened spell to repertoire

[cryptfeller]

Hi, I was just trying to figure out how to add a heightened spell to my character's repertoire. For example, I'd like to add Heal heightened to 2nd level as one of my picks as a 3rd level Oracle, so that I can choose it as a signature spell.

I see that the interface allows any spell to be chosen as a 2nd level signature spell, but as I understand the rules, only an actual (heightened or otherwise) 2nd level spell should be able to be chosen?

I suppose the workaround is just to take a spell at its original level, consider it to be the heightened, level, then pick the other spells you should have access to? That'll result in errors/warnings though, so some method of officially learning heightened spells would be nice. Is there some way to do this already, and I just missed it? Thanks!