Simple....
I write in BB. I use it like a scratch pad. Get the idea, grab my guitar, find a style in BB that works, and start working on the song.
Get everything like I want it. Right structure, key, tempo, groove..... save the file.
Open Real band and use it to render the tracks from the BB project to audio/waves and add the other instruments that I want in the song that are not indigenous to the style chosen in BB. For example, a hard rock style, which I often use for country, doesn't have fiddle or steel guitar but RB lets me render those kinds of instrument files.
Export the files to Sonar and mix.
I think PG was working on a project kinda like this... video of how we work, but IIRC, it got shelved. I don't like doing the video thing on this because each one of the steps could easily be 5 to 10 minutes of detailed instructional information and even after 2 hrs, there would be things forgotten and not said that make a huge difference.
I'm sure someone will provide you the video of what they or someone else has done.
If you have questions about something you hear in one of our songs and want details, just ask.
Then of course, you could look at this:
http://www.pgmusic.com/videos.bbwin.htm PG has a ton of video tutorials up on how to do things. My process uses the stuff in those videos as I'm sure everyone else's does too.
User to user videos>>>
http://www.pgmusic.com/videos.user.htm