GTalk URL?

I've been trying the various techniques to get GTALK to popup when a user clicks on one of my web pages, it works for skype but not gtalk. Any ideas as to how it'll work?

What I've been using:

gtalk:chat?jid=gmailhere

No external/internal scripts, it has to be a single link due to design limitations.

googletalk.blogspotXcom/2008/02/google-talk-chatback

Not an option, like I said it has to be a single launch URL like skype://namehere

Maybe I just have to discard the GTalk option as there isn't any such URL supported by google anymore.