creating sheet music

[Stephen Haase]

I have been working with Sibelius to add a piano part to vocal music. I
can get all the notes on the music. My problem is that I need to line up a 
piano part with the vocal parts, and I don't want to transcribe the vocal 
parts. I can get the right number of measures per line, but Sibelius does 
not space the notes evenly throughout the measure when I drag the measure 
to a different length. Can I use music21 and lilypond to create the sheet 
music that will line up with the vocal music and to space the piano notes 
correctly? I would like to know that it is possible before I get all 
involved with new software. My plan is to write the piano part and xerox 
it along with the vocal music. 
      Thanks
           Steve Haase