How To Invert Apple Magic Trackpad Orientation

UPDATE 2016-12-18: as suggested by a very helpful comment, Sierra users can get this back with BetterTouchTool. I can confirm that it works: in BTT Preferences, click on the Trackpad icon in upper-right corner, then in General (Tracking Speed etc.) tab, at the bottom, select "Mirror complete Magic Trackpad orientation for "upside-down" usage. BTT is an awesome utility with plenty of other features and constantly adding new ones (I've been using it for a very long time and wasn't even aware they had introduced this option!), and it's incredibly cheap, so you should definitely check it out.

UPDATE 2016-10-01: It's all over, folks - OSX 10.12 "Sierra" officially broke this trick. The only suggestion I have left is to "flatten" the mouse with a book underneath, long enough to give you wrist support.

UPDATE 2015-10-30: Various commenters noted that the following hack doesn't work with Magic Trackpad 2. I cannot verify this; I can only say that the original version I have (model no. A1339) still works the same way with OSX 10.11 "El Capitan".

Over the years, I've grown so fond of OSX trackpad gestures that I couldn't bear the thought of going back to a mouse when I bought my Freestyle2 keyboard. The solution was to buy a Magic Trackpad, which works exactly as expected. However, Jony Ive's people clearly ignored ergonomics when designing this product: in the default configuration, it's just a wrist killer.
I wonder if somebody knew about this, because OSX has a very easy way to turn the trackpad around, in what becomes a much better stance; a negative slope is much kinder on your wrists and hands. So, without further ado, here's how you revert your trackpad:

1. Disconnect your trackpad, by pressing the power button until the green light goes off.
2. Type the following command in your Terminal, all on one line: sudo defaults write com.apple.MultitouchSupport ForceAutoOrientation YES
3. invert your trackpad, turn it on, then place five fingers on it, stretched enough that the device can recognise a hand shape. Congratulations, your trackpad is now inverted.
4. If you want to go back to the previous orientation, just switch the trackpad off, turn it around, and again place five fingers on it on reconnect.

I suggest adding a padded rest for your wrist, or something to that effect. I'm currently using a couple of CD cases but I'll probably get something softer at some point. Now my wrist feels *much* better, even more relaxed than with a mouse.
Caveat: the trackpad has a significant inactive area where the battery is stored. This means that you have to keep your hand a bit further from the edge than before. It might take a few minutes to adapt, especially if you drag&drop with your thumb as I do. One alternative is to use three-fingers dragging instead, which also works very well.