The flash plugin (flash-plugin-9.0.31.0-release.i386.rpm) can simply be installed as an rpm as usual. The installation also makes a link in the mozilla plugins directory (for now, /usr/lib/mozilla-seamonkey-1.0.7/plugins) to the libflashplayer.so (for now, /usr/lib/flash-plugin/libflashplayer.so).
The java rpm (jre-6-linux-i586.rpm) installs to /usr/java/jre1.6.0/ which is fine, but it never makes a link from its plugin to the mozilla plugins directory. So mozilla never knows it’s installed. To fix this, do:
cd /usr/lib/mozilla-seamonkey-1.0.7/plugins ln -s /usr/java/jre1.6.0/plugin/i386/ns7/libjavaplugin_oji.so libjavaplugin_oji.so
Now mozilla will know where to find the java plugin. We’ll probably have another problem when mozilla gets upgraded to a new version, but I’ll look into a way of automating this.