Paradoks is right. All personnel spells can be cast on your characters by casting it on their avatar. The bodies fade fast and always have. It's not new. I can't remember about the raise body disciplines, but I think it's not described properly. Try casting them on Serena, or on empty space on the ground. It may not need an actual body, the same why the summon animal disciplines don't need an animal.
Edit: Okay, scratch what I said above. There are 2 types of spells that I was getting confused with. There's sommun and control. Summon spells will make a familiar appear, be it animal/snake/ghost/whatever, control spells will make something become your ally for a short period of time. The difference being the later has to be cast on something be it in this case a dead body.
My only suggestion to you is, if you pause the game using the "Pause" key, (it should be next to "Scroll Lock") and then cast the spell on the body. I've been looking and they do fade pretty fast. They'll be gone before the end of the fight most likely. Again, as far as I can remember, this was always the case, but it should be doab;e this way.