To get the Tempo to match a pre-existing MP3(?)
That's how I read it. I've done the same thing before, actually I've done for a produced CD. The drummer didn't want his name on the credits for a given song, so I brought it into RB and using the ACW was easily able to line it up and generate a RealDrum track for that song.

/my usual response for ACW; I use RB for this, as it not only seems more intuitive, it can also handle odd times and generate sections as well as multitracks .. so it's more better for me

I generated two takes of RealDrums on said song and we were able to cut/paste a final track from those that *very* closely resembled the original drummer's tracks
win/win
drummer was happy (and impressed) and so were the rest of us


I do not work here, but the benefits are still awesome
Make your sound your own!