In the older waveform window, you must plot the
vs(emitterNode))-vs(baseNode) - or just base if
it is a common-emitter setup, which is not the strict
Gummel setup but may be more relevant to the
circuit use. Then plot (say) the is(collector_port)
(without erase) in the same window. Two very
discrepant scales and so on but this is only a waypoint.
Now double-click on the X axis (or Axes -> X-axis) for
an options menu. Change the X axis quantity from
independent variable, to the Vbe you have plotted.
Badda-bing, should have Ix vs Vbe.
I know little, but despise much, about wavescan and
have refused to use it for anything so far. You're on
your own, there.