A quick solution is to add an "s" to your url string (nothing new here).
When I have more time I will take a look at the cookie that's set by gmail chat and the related communication / reference. During a quick test last night, Wireshark complained about some of the captured traffic not being compliant ... more to come.
Saturday, November 11
I use gmail and enjoy their in-browser chat client. In case you don't already know, that communication is in clear text ... sniff sniff.