two-voices per staff question

Hi,

Using prerelease for version 2.0.0 (a925ae0) and wondering why I can't add a voice only in the middle of a score. In particular, I'm playing around w/harmony, and that only occurs midway thru. But anytime I try to click on voice 2 (as described here http://musescore.org/en/node/36056) it assumes I'm wanting to add a 2nd note voice to the first measure of the piece. Is there some way to add voices beginning at a specified location?

Thanks!