You'd definitely have to develop a new style since you can't stand up on a recumbent. I tend to muscle my recumbent up the hills but a lot of recumbent folks use some really tiny gears (<20GI) so they can spin up. When I ride a DF bike uphill I tend to stay in the saddle and muscle it up at low RPMs too. I definitely don't pull back on the pedals at all so I'm guessing I basically rely on a 180 degree power stroke.

The difference that bothers me most riding a recumbent is intersections. I can't rotate my torso as much for looking to either side or looking behind so I have to rely on using a rear view mirror and being a lot more cautious.