You can't use ASIO in more then one app at a time although it will work sometimes but unreliably.
In BIAB don't use ASIO no need to unless you're using the thru channel to play the softsynth live with a MIDI controller. BIAB would have to be a "Rewire" app in order to send the audio to Reaper. At this point when you're happy with the BIAB arrangement "render to wav" and import to Reaper/Real Band and continue.
You don't need ASIO4All

John
ESI Gigaport HD+
Lenovo Turion II /4 Gig Ram/ Win7x64 be
15.6" Monitor
"The only Band is a Real Band"
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