| MrCharisma |
Yup.
If you're using traditional stealth only the first attack will get sneak attack damage (after your first attack the enemy will know you're there and will not be flat-footed against you).
If you're flanking (or using some other way to attack flat footed on all attacks) then all of your attacks will get sneak attack damage.
As for why you haven't thought of this before ... you'll have to ask the GM ;D