Do you know why the difficulty is 1? It sounds like that's either the easiest difficulty or the hardest.
That's how pools work, AFAIK; they send out difficulty=1 hashes for your miner to solve, and there's a certain chance that a difficulty=1 solution will also be a solution for the current, higher, difficulty. Basically, the shares you submit to the pool server are your proof-of-work, just like the full-difficulty hash is the pool's proof-of-work for the full block chain.