I think the USB port on the FR-18 is designed to receive a memory stick to transfer keyboard setups and other customization tweaks. Pretty sure you want to use the FR-19's midi out with an appropriate cable into your computer's sound card or other hosted midi in to trigger recording software. I think you'll end up running the software synth in that computer program, using the FR-18 as the input device (controller). I tried it once with Reason, and it worked as a midi controller with that type of setup.
I might try that next, but the manual says either the midi or the USB will accomplish the same thing.
Given that insight, I just RTFM again, and I think I was the victim of my perpetual skimming when I read. I'll try the MIDI cable. I thought they did the same thing, even after skimming several times.
I'll give further progress on how effing witless I can be.
Sorry I meant "they" and not "we". My computer auto corrects if I type "te" it inserts "we" and I probably forgot the "h" in "they" so it saw it as "we" and not what it should've inserted which was "they". I helped run food stand at the Shrimp and Petrol Fest in Morgan City once. Met this dude from there named Faryl Dupuis. Funniest SOB I ever met in my life.