How to trigger a sustained MIDI note in LogicPro X via MIDI Guitar

I am triggering MIDI notes in LogicPro X via the "MIDI Guitar" app. I would like to trigger a MIDI note, and have that note sustain, so that I can solo over it. I am splitting my guitar signal thru a volume pedal via a “Jam” adapter into my MacBook Pro to trigger the MIDI notes and also thru an effects processor and amp. When I de-press the volume pedal the MIDI note discontinues. I want to be able to de-press the volume pedal (no longer triggering the MIDI note), but have the previously triggered MIDI note... sustain. Please offer any instructions on how to achieve this. It is not intuitive, to me. Thank you in advance.

Sandy U.