Using BB drumkits while editing .mid in DAW?

I use Reaper to create midi files which will ultimately be used in BB. Problem is that they obviously sound a lot different while I’m editing because I’m hearing them through a software synth in Reaper. Is there any way to get the BBM drumkit sounds to play those .mid files while I’m editing?
In BB manager, when are the .mid files actually loaded: when you click on each part or when the song is loaded? Any way to play the changes in BBM after each save in Reaper?

Use your BB as an external instrument from Reaper. Monitor the output from the BB. You’ll go from your midi interface out to the BB midi in. You’ll need to have Reaper sending on the same channel that BB is receiving. BB midi-in settings need to have Note On enabled. Select the drum kit you want to use from the BB, and playback from Reaper. This may give you some more insight.

What Phil said…

You may need to create some Drum maps to make life easier.