I have b.i.a.b. 2005. I'm really into making my own styles (with m.i.d.i. of course) Does the new b.i.a.b. allow user to create original audio styles ? Does realband?

You can make your own RealDrums but not the RealTracks. That's because RD are much simpler in that they only have to follow the tempo not the chords. It's not likely, but perhaps not impossible, that PGM will ever release a developer interface, or instructions, to create audio RT. We'll just have to wait and see on that one.

But if you like BiaB 2005 I highly recommend you upgrade to 2008.5 since there are many improvements in the new version. Upgrade prices are pretty good too.