Meta Key on a MacBook ?

I have some difficulties (ok let’s be serious - i don’t find any way how it could work) with the Meta key. When I’m in the normal-snap mode, I don’t find how to bypass that snap.
How could i configure that key ?

However, there is some keyboard shortcuts that do not seems to work.
Alt-s for example (Split at edit cursor)

Alt-e and Alt-m are working…

Running ardour2 beta12

Has someone any idea ?


I forget :

I’m running MacOSX 10.4.9 in french on a MacBook Core2DUO 1.83 GHz, 512 Mo Ram.