Adding parts at different points

Hello,

I am transcribing an already written piece of sheet music into MuseScore. The first line of measures has just a piano part. The second line, a vocal part is added (the entire part did not even exist before, but in the next line down there is a stave and clef and key and line connecting the piano part to the vocal part)

I'm having trouble putting this in MuseScore (using v. 1.1). Could someone explain to me how to do this?

I tried going into Measure Properties and un-checking "visible" on line one for each of the first measures, which worked to a degree until I had made everything completely invisible except a single line coming up from the piano line, the one that would connect the two parts if it was there. I don't know how to shorten or remove this line.

I tried using a spacer and shortening it. Nothing.

Thank you for your time.