There's not a lot of information on how "virgins" of other types of White Court vampires work. Most of it is speculation since Harry hasn't had a lot of experience with them.
I think the reason for that, really, is to discourage people from playing White Court vampires of those types. We've seen that a lust-feeding vampire can try to control his hunger and act in a morally acceptable manner, yet still stay fed, but fear and despair are much harder to get without harming others.
Edit: As I understand it, though, to become a full vampire, the character has to kill by feeding on whatever emotion it is they feed upon. So a pain-feeder would likely have to torture someone or beat someone and feed off their pain. I'd say it's likely that Malvora, Skavis, and any other houses that don't feed on lust (maybe even some non-Raith houses that do) would raise their children in full knowledge of what they are, and train them for their first kill.