Is very easy u need the newest Thunderbird Client (Download)…
After that you must open your Thunderbirg Console and copy this code:
Components.classes['@mozilla.org/appshell/window-mediator;1'].
getService(Components.interfaces.nsIWindowMediator).
getMostRecentWindow(“mail:3pane”).document.
getElementById(“tabmail”).openTab(“contentTab”,
{contentPage: “https://wave.google.com/wave/?nouacheck”});