You may well be able to work it up doing a few steps. Maybe start with 0.5L and let that do it's thing, then 1L, then 2L until you get enough yeast. My only experience with that yeast was a stone dead smack pack.
That said, I would be tempted to bring that back to the place you got it and say "hey, how about giving me one that isn't expired". Starting with limping yeast isn't going to make things any easier.