I'm going to attempt to explain the way the DSG operates in reverse - perhaps it will help you understand and therefore be able to make it behave more smoothly.
The first and most important thing to remember is that the DSG is coupled to the engine with a CLUTCH similar to a manual transmission. When backing up a hill, the DSG will elevate the engine RPMs to about 1500 RPMs (exact number isn't important). The thing that confuses most people is that the throttle pedal actually starts to behave like an inverted clutch pedal, in that applying more pressure to it will engage the clutch more. If you're not used to this, it can result in jerky behavior.
Be smooth with the accelerator and make very small adjustments. Engine speed will not correlate with vehicle motion like it would in a conventional automatic transmission. A little practice and paying attention to how the vehicle responds to your right foot and you'll be backing up nice and smoothly.
