Sorry! I did look it up, altho i have no first hand knowledge.
It looks like the answer is - it depends. It depends on if you are applying for the first time. If so, then if you already make around $1300, they will not approve you. However, if you DO get approved, then you can make around $1700 OVER the $850 SSI payment before they will discontinue your benefit.
Thats how it read to me.