Joomla Single Sign On with a CAS server #

Hello, we have a software under developed in Java, and it user portal (documentation) is done in Joomla. Now we have to integrate the these two environments. Software already using CAS authentication and joomla usind default auth. We already installed a component called external login, and it works. We need to make the submit button to be automated. My customization of the module would be great. But we need to do some custom on it, we need to: make users logged inside these software arrive in joomla logged by now is only this,