look on the bottom of the stock reg, theres 2 little flat spots for a wrench. you have to take that little cap off to get to the adjustment screw. if you still have the steel braid line on there you may or may not have to remove it too, cant remember.
make sure the ivg just isnt turned in too far, should be about 2-3 threads in. unless the reg has been previously adjusted it should be set where it needs to be from the factory, then you can just use the ivg to fine tune.