OK, I'll try that and get back to you.

  hey gang, I've tried everything that you've all told me and I still can't it to work. To my ears, the acoustic guitar is still *behind* the drum loop when after I set Autostretch and then speed up the metronome. It only works at the original tempo that I recorded the track. I guess I'll have to email CW support. I can dropbox the file to somebody, if you want to look at it. just PM me.

I'm on my phone so I can't check to get the actual way to do this but if you have your drum loop set at the new tempo you should be able to grab the end of the guitar audio clip and drag it to suit. I think there is a modifier key involved (possibly SHIFT) but it isn't complicated.

Grum.