beams on melisma

[ludovic sardain]

Hello,

In older versions of Lilypond (before 2.0), the lyricsto command was 
different: melismas were detected by the slurs or ties, and the other notes 
were unbeamed.

Now, the function is the same, but all the notes are beamed. I want to know 
if there is a command to restore the previous way. I know that I can remove 
all beams and add manual beams on the melisma, but it's less convenient.

I like to have both slurs and beams to show the melismas.

Thank you

Ludovic