I find I get a lot of small, niggly problems when I try to drag instruments from the BIAB VST into Reaper...a frequent one being that the drum track isn't in the drum slot, so to speak, so I'm not certain when dragging which will be which despite their labels.
I find it easier, well - more reliable - to export audio, using the BIAB audio export feature, into my Reaper Project folder. Remembering to select the right boxes so I get individual, dry, centred tracks is the only complication.


Cheers
rayc
"What's so funny about peace, love & understanding?" - N.Lowe