Normally when we press the alt key we have access to the toolbar with the keyboard. I have KDE 4.3.1 and i dont have this function, in any application. Is there another shortcut ?

Do you mean the menubar? Toolbar shortcuts usually begin with, e.g. Ctrl+S for save. To access the menubar, however, you can press Alt+[Underlined Letter], e.g. Alt+F for File. Both work for me in KDE 4.3.1.

May be because i have greek localisation it does nt works for me. I try with both keyboard layout. It has to be a bug with the localisation

Oh. There's a bug in Qt and keyboard layouts, see my topic here (seems like a lot of text disappeared after the migration, though )

My workaround is to use the setxkbmap command to switch layout.