Thanks Niko for this reply...
My problem is that i need to perform actions at shutdown... not only shutdown the computer. If i use shutdownwanted, and if there is any other package scheduled (setup in configed), it will launch actions without informing the user...
So, my idea was to add a package named actionsWanted.opsi with a high priority (95) that would ask for the user if he wants to let the localboot products to be installed... The package i have launches an autoit script that ask a question, minimize notifier.exe and winst.exe and pauses the execution of localboot setup.
But that's not very fine...
I found on the wiki a post where Dark Alex talks about
an event "request_graceful_reboot" which issues a popup requesting the user to reboot
That's why, i am wondering whether it is possible to add an event in opsiclientd "request_actions_launch" for example ?