Unlocking the Sword of Legend with the Boots of Levitation

[Virtua Sol]

I've tried to unlock the Sword of Legend with the Boots of levitation trick and have never gotten it to work. Swinging the sword while levitating doesn't seem to count towards unlocking it, and if you swing the sword after the boss is dead the curse still hurts you if you're on the ground. Anyone have any ideas? I've read in a few places that the trick works but I don't know what I could be messing up.

Edit: So, looks like I miss interpreted some particulars. Apparently someone other than the one levitating has to swing the sword, so it just can't be done in single player.