That's a good question and a very important one.
Since there's no answer yet, I'll ask further questions about beaming, where Notion 3 seems to have a serious problem.
After using an old version of Sibelius for some years, I've tried the demo version of Notion 3 and find that it has many attractive features (not the least of which is the open and constructive attitude of the Notion team, which is a refreshing change
).
But there are very basic deficiencies in Notion's notation capability, and the most glaring one is the severe limitation on where beams can be placed. The way the beam tool works is brilliant, and gives the impression that beams can be placed absolutely anywhere, which is how it should be. Unfortunately this is far from the case. They cannot go over barlines, and they cannot even connect between some of the notes within a bar, as fabiolcati points out above.
This is a very basic shortcoming, and, considering what has been achieved already, should be an easy one to rectify. I'd really like to see Notion 3 succeed, and I'd like to be able to use it someday, but unless it can be updated to a point where it can easily notate passages such as the attached example, I'm sad to say that it cannot be taken seriously as a notation program.