iPod Nano 7th Gen Pedometer not working

I bought one iPod Nano 7th Gen about 6 months ago, and only now i am testing Nike Fitness application, and unfortunately it doesn't work.

I tried to run on a treadmill, but the app doesn't count distance, or steps, after some minutes, the distance is 0 km.

I also tried to walk using "walk" function, and it also doesn't count any step. I also ran on the street, attaching the device at several places like pocket, arms, waist, and it didn't work anywhere.

I am no using any external sensor, all sensor options are disabled on configuration.

I restored the device to factory default configuration, and didn't work...

I just called at Brazilian Apple Support, and they told me that the 7th Gen of iPod Nano doesn't have one builtin pedometer. They told that I have to buy the Nike shoe sensor to work properly.

Does someone here have any similar problem like this?

Thanks!