I don't think it's possible as i remember some people suggested an Import button for normal and bump maps for future version of Sculptris.
And unfortunately pixologic happened meaning this kind of hoped update will probably never happen, so i think it is better use other application , like the Blender you already use, to render your models with an external bump/normal maps.
Big thxanks, taron. It probably looks like children in pregnancy, with nasty face, but I was going for little deamon girls. She suppossed to look like she has anorexia, witch big belly (it unfortunetelly hapens to poor kids from Africa when they have this kind of belly from starvation). But I guess I overdid her belly and now she looks like little girls in pregnancy. WTF you say probably when u see her firs time. hehe