Thanks. I walked through the connect process myself this morning and didn't even find that option
I also tested sending an HTML mail to such an address, proxying to my own real address. The annoying thing about that is that the Facebook proxy removes all links from the mails. We use the addresses for a mailing list, and our mails always has a small one-click unsubscribe link at the bottom. The proxy unlinks that link, and put its own 'unsubscribe' link underneath. If people click that, my system will of course keep sending them mails, so I'm afraid FB may consider it spam at one point.
Pretty annoying. I wish we could enforce people to connect with their real e-mail address. I think there was an extended permission for that at one point, but can't remember for sure.
Anyway, thanks for your help Alex.