BetterTouchTool's "Normal Mouse" area allows you to assign functions to all kinds of mouse buttons and should work for you. It's free, too, so it won't hurt to try.

The author has issued a couple of recent updates to make it more compatible with Lion. There are still a couple of small things but I'm using it every day (previously with my mouse, now with my trackpad) and it's tremendously useful.

lion: assign buttons on a Microsoft mouse
If I connect to my e-mail server via SSL (SMTP/SSL) and the recipient also only checks his e-mail via SSL (web/https or IMAP/SSL), does this - generally speaking - increase the security for the message content in any way? 

That is, will the communication between my providers e-mail server and the recipients e-mail server be "secure"(*), or will the e-mail be delivered plain text between the servers? 

(*) Secure in the context of: encrypted throughout it's transit. Not secure in the sense that I'd put any really sensitive info in there.
