The editing in Biab is too restricted, that's why I showed the Reaper script that instantly transfers the Biab tracks without rendering to wav and dragging in. You are best to use Biab to just generate up the track/s or section/s and the sooner you get out of Biab into Reaper where you have full editing control the better.
Even when you use the Copy Special function to Move tracks, it turns the track into wav files.