http://valinet6l6tq6d5yohaa6gdsf2ho4qcqcxyj2nahp5kd4z7nsa6ycdqd.onion/2015/07/01/How-I-exported-my-text-messages-from-Windows-Phone-to-Android.html
After a brief chat with the guy there, he declined to help me telling that the Nokia/Microsoft devices in the shop (sorry other Windows Phone vendors, but this is the plain truth – other than Nokia/Microsoft, Windows Phone is represented by no one) are running a custom demo software of Windows Phone.