ProGuard breaks javascript access to my Java applet

ProGuard breaks javascript access to my Java applet

I have a jar-file which is loaded into a browser as an applet. On the
webpage, there are several javascript instances which inform the Java
applet what to do. But after obfuscating the .jar file with ProGuard, this
no longer works. The browser console gives me the following error:
Object #HtmlAppletElement has no method 'example'
This is the Java code:
public void example(int i){
dosomething();
}
Works fine without ProGuard obfuscation - I tried many different settings
in ProGuard. What am I missing?