SIGMA DP3 Merrill - Manual (Page 116)

115
Aperture / Shutter speed
Aperture Value Shutter Speed
Original
(Default)
Open Stop down Slow Fast
Reverse Stop down Open Fast Slow
Exposure compensation
Exposure Compensation Value
Original
(Default)
Under Expose Over Expose
Reverse Over Expose Under Expose
Focus Ring
Focus Position
Original
(Default)
Close Distant
Reverse Distant Close
WARNING !!

It is not possible to reverse the direction of the buttons.