Not able to authenticate and configure Seraph with Jira 5

To upgrade to Jira 5, I need to configure our custom authenticator by using Seraph via the already implemented SOAP web service. In the Seraph authenticator (named SeraphAuthenticate class), I also override the abstract method, getUser() and authenticate() extending from com.atlassian.seraph.auth.DefaultAuthenticator class in Seraph.

Then I compile this as a Atlassian plugin using the command atlas-compile which in turn create a .jar file. I am not sure whether we are extending this DefaultAuthenticator correctly, you can request to have a look at the code if you want. I have then follow the instructions from http://docs.atlassian.com/atlassian-seraph/latest/configuration.html, which is configuring the seraph-config.xml and web.xml. I am not able to get any authentication while I try to login.

For info, I have tried on SeraphAuthenticate by giving some parameter, username and password and it is able to authenticate via SOAP and return true or false value. But it seems everything is lost when I could not get any authentication by using this class. Can you provide me more information to configure authentication using Seraph other than override the DefaultAuthenticator class? I am in no where now, and would like you to enlighten me with some idea so that I can proceed with this authentication.

Thanks.