Baal, I don't have any advice for you, but I figured I would at least link you to a couple of old threads where another forum member (JoeStIdes) was successful in getting the tutorial character (Tiffany) into XSP 3.5. Be warned, collisions did not work and very little (if any) interactions were possible. Also clothing did not work (probably because of no collisions). Linking you to these threads because they were kind of buried deeper in the forums so maybe you missed them, and maybe something there can help you:
"Managed to insert tutorial character"
viewtopic.php?f=27&t=3834"managed to insert tiffany into dungeon in 3.5"
viewtopic.php?f=27&t=4021He was kind enough to detail his process on how he got her into the game in those threads. Maybe you can figure out how to get collisions working?
Good luck!