Save the text below as enableJava6.sh in plain text format.
Open a terminal and run the command. That will reactivate the old plugin and should work fine. Credit due to Rich Trouton.
#!/bin/sh
# Checks for backup directory for Java 7 plug-in
# and creates it if needed.
if [ -d "/Library/Internet Plug-Ins (Disabled)" ]; then
echo "Backup Directory Found"
else
mkdir "/Library/Internet Plug-Ins (Disabled)"
chown -R root:wheel "/Library/Internet Plug-Ins (Disabled)"
fi
# If a previous version of the Java 7 plug-in is already
# in the backup directory, the previously backed up Java 7
# plug-in is removed.
if [ -d "/Library/Internet Plug-Ins (Disabled)/JavaAppletPlugin.plugin" ]; then
rm -rf "/Library/Internet Plug-Ins (Disabled)/JavaAppletPlugin.plugin"
fi
# Moves current Java 7 plug-in to the backup directory
if [ -d "/Library/Internet Plug-Ins/JavaAppletPlugin.plugin" ]; then
mv "/Library/Internet Plug-Ins/JavaAppletPlugin.plugin" "/Library/Internet Plug-Ins (Disabled)/JavaAppletPlugin.plugin"
fi
# Create symlink to the Apple Java 6 plug-in in
# /Library/Internet Plug-Ins
ln -sf /System/Library/Java/Support/Deploy.bundle/Contents/Resources/JavaPlugin2_NPAPI .plugin "/Library/Internet Plug-Ins/JavaAppletPlugin.plugin"
# Re-enable Java SE 6 Web Start, which allows Java
# applets to run in web browsers
ln -sf /System/Library/Frameworks/JavaVM.framework/Commands/javaws /usr/bin/javaws