From this thread (http://arch01.forum.helldorado.fr/index.php?topic=1168.0) by Geof:
For the sake of simplification, the weapons of Samael, Sister Eloise, Charon, and Thirty deniers lose their damage types (slashing or piercing).
Then an addition to the Spiritual damages special ability:
"As long as a weapon is benefiting from the Spiritual damages ability, it loses all other damage types"
Thanks for that, i'll add a note to my english rules
cheers god to know ...