How to configure firewall to allow Java connections

Hi,

I have a trouble with Java when I set custom firewall settings ( the third option ) in OS X preferences.
Every time I open a web page that has a java applet it asks me to authorize the incoming connection (it is a chat applet) and I have to allow that every time I go there.
That happens when I set the firewall to use custom settings: I can manually set which applications are allowed to use network connection.
Unfortunately it seems not possible to add Java to this list because it is not listed as an application and so I don't know how to select it. By the other side, my choice to allow java to use the network, seems not saved in this settings like happens for other apps.
I see that Java should be located in /usr/bin/java ... but how to tell it to the firewall?
Or how to get rid to this repetitive request?

thanks!