Well I actually asked them through support email. I tried posting in their forum but couldn't access although i am a member......Anyways i just adding our conversation below. i am satisfied with your product and support so i will surely purchase jfb connect. the best feature that using facebook connect not only user can login but register too which is the main issue with default jomsocial plugin.
me: the installation was smooth and everything is running ok till now except few issues. I have a problem using facebook connect and please try to solve this problem or else my website functionality is highy compromised. Connecting with facebook is working fine. The problem is if someone register to my website using my login and then connect via facebook and click on already a member then he cannot login using our website login and password. Similarly if someone register using connect with facebook then next time he cannot login using our website login system but only via facebook. So the basic problem is using facebook connect a person cannot log in to my website unless he uses facebook connect. How do I integrate both username and password of facebook and my website so that the user can use either to log in.
jomsocial: This is actually the default behavior of the Facebook connect plugin and there isn't any work around for this yet.
me: The facebook connect problem which I mentioned definitely has a way around. Please check the plugin from jfbconnect at
www.sourcecoast.com/joomla-facebook/ . I have tried their demo and it works just fine. Please try their demo and maybe you could find a solution which I am sure will be great for both of us.
jomsocial: They are using an alternative method for their Facebook Connect and they have written an authentication script which bypasses Joomla's security which is not what we intend to do here.