first, you may well select more than one audio output bus, while on the export dialog; you can select Master *and* Drums altogether and they will mix-down all the way through the exported file;
second, due to hard-coded internal processing flow (that is, you can't do anything about that, kinda feature, not-a-bug, sorry;)), making an aux-send insert on an audio output bus will only work *iif* the source bus is listed *before* the target one--so that it won't ever work if the target is "Master Out" which coincidentally happens to be the very first and top default one.
hi manu,
first, you may well select more than one audio output bus, while on the export dialog; you can select Master *and* Drums altogether and they will mix-down all the way through the exported file;
second, due to hard-coded internal processing flow (that is, you can't do anything about that, kinda feature, not-a-bug, sorry;)), making an aux-send insert on an audio output bus will only work *iif* the source bus is listed *before* the target one--so that it won't ever work if the target is "Master Out" which coincidentally happens to be the very first and top default one.
hth.
cheers