With WinBB you can just add your own Drum Style folder
eg: RockBeat in that folder you will have RockBeat_120_Style.txt
RockBeat_120_Style.wav
or wma (in Mac wav aiff or m4a)
and you just click Rebuild in the Drum Picker window then it will show.
In Mac correct me if I'm wrong but the only way I found to get them to show is:
add drums to the bottom of (good idea to make backups of the txt files 1st)

Applications/Band-in-a-Box/Data/PGALLDrumFolderNames.txt (this is the list that shows when you check "Show RealDrums that are NA" in the Drum picker window, if you have any of those drum styles then they will show)
Quote:
...........
C:\bb\Drums\UrbanPopEv8UrbaFolk^\UrbanPopEv8UrbaFolk^1-metal,clap
C:\bb\Drums\UrbanPopEv8UrbaFolk^\UrbanPopEv8UrbaFolk^2-kick,brkdn
C:\bb\Drums\UrbanPopEv8UrbaFolk^\UrbanPopEv8UrbaFolk^3-cycling
C:\bb\Drums\RockBeat

Tags to
Applications/Band-in-a-Box/Data/DrumStylesInfo2.txt

Quote:
..................
UrbanPopEv8GoodGirl^=4,Ev,8,Pop,Techno;HipHop,95,120,Ed (Great Oz) Clare,16
UrbanPopEv8Requiem^=4,Ev,8,Pop,Techno;HipHop,70,130,Ed (Great Oz) Clare,16
UrbanPopEv8UrbaFolk^=4,Ev,8,Pop,Techno;HipHop,80,120,Ed (Great Oz) Clare,16
RockBeat=4,Ev,8,Rock,Pop,100,140,www.rockdrums.com,NA

Info to
Applications/Band-in-a-Box/Preferences/RDUserMemos.txt
Quote:
............
››RockBeat
In the Style of Phil Collins . . .
a - HiHat, Snare
b - Ride, Snare

Suggested tempo range 120 - 150


Below is a screen shot after adding MotownShuffleGrove



More:

http://www.pgmusic.com/tutorial_realdrums_stylemaking.htm