It seems the SMF posts were imported in the new vBulletin forum using the SMF account name instead of the screen name (or some other association mechanism that leaded to the same result).
I used to have an old Curse account named Elisios. When I created my WowAce account, I used the same name but I set another screen name, that I am widely using now: Adirelle. When I saw they was a plan to move from wowace to curse, I created a Curse account named Adirelle and moved all my email addresses from Elisios to Adirelle.
Now it seems all my posts of the old forums have been imported as posted by Elisios. Is there a way I can take ownership of this posts ? (I could MP any site admin the current e-mail address of Elisios account to authenticate myself).
On a side note, when trying to connect as Elisios on the forums, I've got a "redirection loop", that prevents me to do anything with that account.