small staff after normal staves

Hi all,

I have to edit some folk songs and, at the end of most of them, I need to insert a small staff where I notate the variations that occur in different stanzas of the same song. The file BB867 below it's an example of how my scores should look like.

In musescore, my approach was to insert a line break after the end of the song and then to add the few extra measures below. The problem is that, when I tick the 'small staff' option for the last staff, the entire score gets smaller, not only the staff I need. Is there any way to achieve this alternation between normal and small staves?

I'm on a Mac OS X 10.6.8 and I use Musescore 1.2.

Thanks!