Place a break point at the top of the UIFigureKeyPress function. Press a numpad key and look at the value of event.Key to determine the key code for numpad keys. Then add those values to the cases.
Multiple case matches are combined in cell strings.
After running these two lines, press different keys while the figure is current and look at the command window outputs.
uif.KeyPressFcn = @(h,event)disp(event)