There are surprisingly many shots that look almost impossible to take out on the backhand, but actually turns out to be perfectly feasible. Castle Cover on Medieval Madness is a good example.
The difficulty lies in the margin of error is normally very small. It depends on what you are aiming for: if you are aiming for above Caste lid margins are indeed small. A backhand on the Ring Master in Cirqus Voltaire, on the other hand, are fairly easy to complete.
There are no magic tricks up your sleeve. The biggest obstacle is mental - to realize just how much it is actually possible to shoot at a seemingly "wrong direction". You have to try and error. Because it often requires great precision, it is recommended to take back hands from the captured ball.
Some back-hand can not be taken from a captured, and thus stationary ball. Take for example the catapult on Medieval Madness. From the stationary ball is an impossible backhand. But with a stationary ball position, one can, by pressing very quickly on the flipper button, "patting" the ball a little bit at inlanen, then the flipper up letting the ball roll out a bit. When the ball is far enough out there, and preferably is about to turn back, you can take virtually any backhand shot that does not require too much force.
