i have picked them several times, "offhand" and "onhand". I use a normal tension tool, but i insert it not from the front but from the side in the cylinder. So it is only possible to tense it clockwise, counterclockwise tension tool will slip out of cylinder. So you can only open the double lock by picking, then you have to open cuff by shimming. But shimming is very easy.
Cylinder has three pins and one additional pin on the opposite side, dont forget this pin or you will never open the lock. Here is a picture how to hold tension tool when picking cuffs onhand:http://www.andys-handschellensammlung.de/main/handcuffs_world/saf_lok_mk4/saf_lok_mk4_en.htm
(scroll down to the last picture). Picture is posed but it looks the same when you really pick the lock.