[Pharo-dev] Announcement from removing classes

Hi all, I registered myself to the SystemAnnouncement of removing classes. This works fine when I manually remove a class from the system (either class or package), or do this by using the code equivalent. But when I unload the package using Monticello, no event from removing (unloading) the class comes along. I cannot find the event that I should register to. Can someone point me in the right direction? Thanks in advance, Diego