Hi
as far as I know in the old Buzz there was the possibility to record with the multitrack feature of the overloader ... o.k. overloader is dead. Sgorpi has written a plugin called multitrackwriter ... as far as I know it is still available at buzzmachines. Therewith you can record several wav-files at the same time ... one for each instrument, or effect, everywhere, in every chain ... (as long as your CPU and harddisk can take it) and you can see (and set) the recording level. A pretty cool machine though ... just sometimes in the new Buzz it sets the volume to 150 percent and you don't have the chance to set the correct level until you restart Buzz ... .
I'm almost sure you can do the same with the ldmixer, but I haven't tried this myself.
Hope it helps ...
and it is what you meant 
I don't know if it works with the render feature of the new Buzz, but it works with the simple recording ...