I think a more hands on view is needed.
When attacking Dark Curse I elect to spend my target lock.
The dice has already been thrown and are on the table.
I spend my target lock, returning the tokens to the stash.
I then elect not to reroll dice as stated in the FAQ.
I never touched the attack dice so when we check Dark Curses text we find that no dice was rerolled, and that satisfies his ability.
Any ability triggering from spending the target lock is now going to take effect.