I made this tutorial for UserTrack Drums but found out that when the tempo map is saved in the SGU it rounds each tempo off that causes everything to be out of sync so until that is fixed in Biab use RealBand.

If you have a live recording you want to add track to and the tempo varies a bit in you drum tracks just load it into ACW in RB (as Biab doesn't do an accurate tempo map) and ACW will quickly line up the beats to bars, just set the first beat of bar 1, then adjust any bar markers if need be, ACW will do the rest. You will have chords but you can Edit > Chords > Delete then enter the chord of the song.
You can then click Metronome > write to track,
this will give you a tempo mapped midi you can drag into any DAW first then the audio tracks.

Full screen

Now to convert it to a constant tempo for a UserTrack or use in Biab:

Export the the Metronome midi track by dragging the track number to DROP MID.

Drag the Midi into Reaper (Reaper is free to try n try http://www.reaper.fm/download.php ) import the tempo map of the midi file.

Drag the Drum track into Reaper (and instruments).

Create an Action Hotkey to move to next beat and insert Stretch Marker, Actions > Show Action List > New .

View show Master Track.

Right click on Tempo points > select all

Right click on Tempo points > reset points to zero/center

Highlight from start to end.

Item > Snap Stretch Markers within time selection to grid.

Save Track/s to wav

Now you can bring it in Band in a Box, RealBand or PowerTracks with a constant tempo.

This process is so much better and precise than the manual process I did when I processed an old mp3 for the Xtra Styles contest a few months ago.

Thanks for posting.

Charlie