The am should function normally. The main impact will be on the batteries - which will not last as long as they would in normal temperatures. Make sure to bring your charger and if you have spare batteries, keep them close to your body when not being used.
I just came back from chengde of hebei, at night temperature was about -10 degree and in the day was about -2to 5 degree, so far my D80 and flash have no problem, I have been holding the camera in my hand all the way, only put back to the bag when on the tour coach. Battery life slightly shorter but I have never need to replace battery in a single day of shooting. So if you take a bit of precaustion, you should expect a happy shooting experience.