Got the API Key from the API generator.
Assigned Yubikey ID to a registered user.
The authentication key (dongle) works good on both Vista and XP platforms. Both platforms recognized and installed the necessary drivers automatically.
Entered username and password+yubikey trigger button on the dongle (do not click the login button on the login form afterwards) simply wait for it to login for you, otherwise you get an "Invalid Token". If you do click the login button and you get the error, simply click on th back button on the web browser.
Couldn't get it to work with Community Builder login form. So I simply activated both Joomla Login Form and CB Login. CB Login module I placed in Registered mode. So it wouldn't display in Public area. Also works with Creative Design popup login form as well.
So far so good. Tested it on four different web sites.
thanks for your feedback, in a very very next version of the module we will implement this feature :)