I'm trying to find a way to select a specific User Performance on the SC-880 via a MIDI message from my sequencer. I was unable to find any relevant info in the MIDI Implementation guide.

Is this possible? If so, how?

Thanks in advance!

Yes on my G1000 I think all SC series.
Insert into MIDI track (Chn) 13 CC00: 120;CC32:0;PC:1 this will select Perf Mem A11 or PC:2 = Perf A12 etc...but before that You have to seting filters in MIDI set