You've been on the right track.
The sustain pedal can be shown in the CC lane of the MIDI piano roll editor. In general MIDI it's CC64 (Hold Pedal). In the dropdown list of the lane's header a CC number is indented (prefixed by a little dot) as soon as there is data of that cc number, so you could look for that hint.
You can also see the pedal event when you switch view to the event list view.
Some good thoughts about accessing controller lanes are cumulated in this feature request:
ME: Easy access to Used CC etc messages.
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