Q:  I have found the piano sustain pedal notation but, when I add the notation
    and play it back, no sustain.


A:  If you added the symbol (from the symbols tool) for a piano sustain pedal,
    a symbol is just graphical so it's not going to have any effect on the 
    playback of the music.

    The only way to get a note to sustain would be to draw in some controller
    information for sustain, extend the duration of the note itself or to 
    record a sustained note from a MIDI keyboard.

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