[Mailman-Users] Global hide/unide list members

[Andrzej Kasperowicz]

A list-owner: http://mail.python.org/pipermail/mailman-users/2004-
March/035696.html
asked me for help with retrieving a list of subscribers of his lists.
What I found on his lists was this option ticked:
"Conceal the member's address" in the "Default options for new members
joining this list.". However, the problem now is that unmarking this
option has influence only to new members who subscribe, but the old ones 
still have their addresses hidden, and I don't know how to unhide them 
globally - all at once (there are thousands of subscribers, so it'd be a 
time consuming task to do it manually for each subscriber). I don't think 
he has an access to shell to retrieve list members in another way.
Is there any way to unhide them all at once?

ak