You\'d probably want to try bulking out your armature/wire. Basically just sculpt a simple \"skull\" sort of shape a bit smaller than the finished head you want. Do this on your wire/stick, bake it to harden it, then you can sculpt the final face a whole lot easier afterwards. You can use an epoxy putty too, just make sure it\'s something that can withstand the heat you\'ll use to bake the polymer clay later.
This is what is commonly done for just about everything, so I\'d assume that is what was done. Since sculpey doesn\'t stick to stuff that well.
I recently got some epoxy glue called JB Weld from the auto section of the hardware store. It can withstand high temperatures (I guess due to being used for vehicles and such) so I\'ve been thinking about trying to use that as a fixative for the Sculpey to wire. I know the sculpey could just tear away even if a layer was glued down but I don\'t think it would. Hopefully it wouldn\'t set off the polymer clay curing. Pretty sure super glue can\'t withstand the heat or I\'d just try that. But I digress...