Ah, well now I think you're talking about something different, that for women doesn't actually have that much to do with sexual orientation.
I could, using your own words, engage in "normal" sexual activity with living men or women, without even being attracted to them. (I'm a female necrophile btw). But that doesn't have anything to do with my sexual orientation. Sexual orientation doesn't perfectly match up to who you have sex with. Ask anyone who has a paraphilia they haven't acted on. It also isn't as simple as "conditioning yourself to a certain stimulus".
Going back to ElKahn's topic though...he happens to have pedophilia and sadism as a sexual orientation of sorts. Based on this, I don't think conditioning will really do much to help him. He was never conditioned to be a pedophile or a sadist so I don't think he can be unconditioned.