The sustain pedal works fine in my Studio One.
If you don't have the sustain pedal mapped in Presonus Control Link, then it works without doing anything. I use this method. And i suggest you use this method unless it's better for you not to do so.
If you have the sustain pedal mapped in Presonus Control Link, then you have to assign the sustain pedal to the plug-in sustain.
I suggest you don't use this method. It can complicate using the sustain pedal in your work. But if it don't then do as you think is best.
My answer was about the Wurlitzer V. My Sustain pedal works with the Wurly V in Studio One as described.
Can't tell whats the matter with yours then. But perhaps a reinstall of Wurly V would help. Don't know.
EDIT: I can add the pedal works with Wurlitzer V in both Studio One 2 and Studio One 3. Just tried in Studio One 2 also.
I use a Novation SLMK 2 controller.
I also use the latest update of Wurlitzer. If you don't have the latest update, that might be a coarse. If so then try to update your Wurly.