Even if you're a good greenside bunker player, you can't use the same technique to reach the green when the bunker is 50 yards or so from the putting surface. The following are the adjustments you need to make.
Take more club. You won't need all the bounce that your sand wedge provides, and the lower amount of loft on your pitching wedge or 9-iron will help you carry the extra distance.
Open up less. Open your stance and the clubface only slightly.
Don't dig deep. Don't dig your feet into the sand as deeply as you would in a greenside bunker. You need some lower-leg action here.
Make a U. The sharp, V-shaped swing you normally make in a greenside bunker is too steep. Instead, make a U-shaped swing and hit the sand about an inch or so behind the ball and make sure to follow through. Your ball will still ride out on a cushion of sand, but the less lofted club and rounder swing will help you fly the ball to the green.