How to Automate IBM HOD 3270

need to automate a mainframe application using 3270, but in this case the terminal is emulated by Java applet and when I try to connect to the url, using LUid and port. This applet is showed in the image.

When I open the applet, I have the LU number

I try to connect with this command c3270, but I need to automate this task, but this systems use JAVA applet.