I have a 2013 'wing.
Yes it does have reverse which is engaged only at standstill by engaging a button in to select reverse, and then a second button which while pushed actually drives the bike backwards using the starter motor.
The engine has to be running to keep the battery charged.
Dealer confirmed my question when I bought it that this function is designed to be used every day if required.
After a couple of goes it becomes easy to use, reversing nearly 500 kg of 'Wing and fatty (me) along the drive and up into the garage.
When the select button is first engaged it locks the transmission into the reverse function, so the bike won't move at all, except when the second button is held in to actually reverse, so if you stop reversing the bike doesn't roll back down the hill.
Yes it's very heavy, yes it's very big - but on the move it has two wheels like any other bike, and is easy to ride. It does run out of ground clearance early, but it motors on quite well - have a look at Mark "Weeble" Mannings photographic website and you can see some pics of me going around Cadwell park during a Lincs Road Safety course.
http://www.trackphotos.co.uk/p890293920
Why have a joined this forum? - Because on that course most of the instructors were on GS and GSAs, and boy can they make those bikes go, stop and manouver - hence I am going to get one as a second bike.