In FL you can work with the Editor if you set the UNO Synth in MIDI Options on no only Channel and disable the Output. This should be look like this :
MIDI in: -- MIDI out:--" maybe it works even if you enable the Output. But I don't test that. If editor is open you now can create a Sound like in Standalone mode. But in FL it's not sending notes through the Editor- even if you enable that (Tested with intern sync). But if you not open the Editor and set a MIDI channel for in and output In the MIDI settings and enable UNO synth, it's sending MIDI messages. I prefer the "MIDI OUT " PLUGIN. You just need to create all the parameters in the PLUGIN you want to control. It's more work, but it works. Set the MIDI OUT PLUGIN on the same MIDI channel like the UNO synth (on Input) and everything works. Now you can link the knobs to a USB controller and everything works fine.