How to kill those annoying popup window with keystore password

We have a java applet which we ship over the ssl and that applet is accessing system properties on local computers because it prints 开发者_如何学Gosome raw txt( we use java dialog etc.). We did sign java applet and we did import certificate in web browser(mozilla firefox) and it works pretty well, but when applet runs, that annoying pop up window appears prompting for password. Clients need to hit OK button, not cancel or close button, and afterward the can print. If they type something, than applet will not run until they have their computer rebooted.

How can we solve this problem? Thanks in advance