Restore notification area on panel

Hello all :)

primarily, sorry for my noob english, I am happy to be part of this community.

I have a banal problem but i can fix, i wanted to delete the evolution icon from the panel but i delete the notification area (volume, network signal, clock, date..).
right click on panel, add notification area, not fix the problem, i have reinstalling the panel from terminal:

:~$ gconftool-2 --shutdown
:~$ rm -rf ~/.gconf/apps/panel
:~$ pkill gnome-panel

but not fix..

Thanks in advance for help.