Every time I enable my Gmail account (Google Talk) in Messages, I get a message asking if I wish to continue with an unsecure Jabber login. This message reappears every time I open Messages on OS X Mountain Lion, and every few minutes if I keep the account on.

I could just click "Continue" each time, or better yet, disable the warning in Settings, but I would rather connect with a secure login.
Is there a way to get Messages to connect securely to Google Talk?
