Comment 8 for bug 200078

responding to myself...
at last, I could make it work
you dont have to re install firefox or java or bother about 32/64 bits support
java 6 and firefox-3.0b4 are already installed in Ubuntu 8.04 beta 64 bits that I use
but there is no symlink between them [there are 1/2 dozen other symlinks that do not work]
cd /usr/lib/firefox-3.0b4/plugins [not any other]
sudo ln -s /usr/lib/jvm/java-6-sun/jre/plugin/i386/ns7/libjavaplugin_oji.so [_oji is important]
then about:plugins in firefox shows the java plugin
and applet is recognized