Reaper as a Slave - Modulation

Hi guys, how i can modulate vsts in reaper as a rewire in renoise. I know That Should work with instr. midi Control. But i am to stupid for this. I want to use the renoise lfo, because the reaper two ways of making lfo are limited.

Ok, now a few synths like uhes and surge works with synths intern midi learn and moving a fader in instr. Midi controler. Reason rack dont work intern. How to Do that with reaper trim?