[Pharo-project] Working with weak announcements...

Hi, I'm working with weak announcements, trying to make it work, and I have a problem in #on:do: protocol (or #when:do:) I try to explain: This method receives a block, not an object/selector, so I can't create a WeakMessageSend which is the appropriate message to handle in other cases. Well, the real question is... how can I produce a "Weak BlockClosure reference" who can die if receiver dies? I tried some hacks (really ugly hacks, btw), but fail completely. Any idea? best, Esteban