Ok, so for you guys that don't solo to good, or can't quite keep things going on the keyboard, read on.

After using Johns tips to create your own user track, Thanks again John. I got to thinking about how they could be done using BiaB, but without me. I know I'm lazy. For starters we all know how good the RT's sound so I didn't want to use the same instruments. Good old midi to the rescue, but midi is not audio I hear you cry, true. But is can become audio when rendered in BiaB or they way I did it and exported a midi track to Cubase. But, let's back up a bit first. So you follow Johns directions and you have your usertrack song that is waiting for you. Using melodist or soloist depending on how you want things to come out, create a midi line over the song you have, voicing doesn't really matter at this stage you just want a solo line. I then drop this in Cubase, select a voice from one of the synths.
Add any effects I might want, then export as a WAV file. This then goes back into BiaB in the usertrack song I created gets saved and works quiet nicely as a User realtrack with no playing from me.

Now the as you can see the options are endless and are really only limited by your imagination, you can end up with background URT's that are pitched to whatever chords you put in new tunes, you can use more than one track in the DAW, it tried an ethnic flute(very breathy) and a lead type sound. Slowly evolving voices make interesting backings. All of this might not be to everyones taste, but if it inspires creativity that's a good thing.

Chris..

Dell Optiplex i3 quad core,8gb mem,500gb
nvidia gtx750graphics,
Win10
ESI studio monitors
Presonus AudioBox iOne interface
Presonus Studio One 3
BiaB2014