Hello,

There are a few options within Band-in-a-Box and RealBand. If I wanted to do Hip Hop music I would personally use RealBand as you can layer multiple tracks and easily loop sections by using the cut and paste tools.
Try generating a RealDrums track in RealBand and finding a few bars that you want played over and over again. Cut these sections then paste them on a separate track. Try adding effects to the track, like distortion or change the frequency using the EQ.
I would also suggest generating a solo track for an instrument like a sax or a flute, clarinet maybe, and listening through until you hear a hook that you really like. Cut that part out, paste it multiple times on another track and then play it back with the drum beat.
Do the same with a bass track, for this you could use MIDI or a RealTrack.
Start with the drums for a few bars, then add the bass. Next throw the loop on top and leave a break for the verse. Make sure the person rapping has a catchy hook for the chorus (or you could sample one) and you've got a hip-hop song.

Dave
PG Music