I read today (sorry, I can't find the link right now) that FMC installed in US (onboard Tu-154M 101) can be used to "fool" the autopilot and generate virtual ILS glidepath that in turn can be used to go around in automatic mode (hence in that situation "Uchod" button would work regardless of real ILS present or not on the airfield).
There was no conclusion if it was programmed to work over Smolensk North.