how to set Djava.net.preferIPv4Stack=true

[Jack Howarth]

    I have tried both the sun 1.5 JDK and the IBM version
using the jpackage nosrc rpms on FC4 and in both cases, the
http://www.java.com/en/download/help/testvm.xml web page loads
a red X for the java applet. I have read that one can use the
-Djava.net.preferIPv4Stack=true flag to solve this problem with
ipv6 but have been unable to get it to work. I thought I should
add '-Djava.net.preferIPv4Stack=true' to the Java Applet Runtime
Settings' Java Runtime Parameters field in the Java Control Panel.
However this doesn't seem to work with firefox. Does anyone
know how to make sure that the java plugin starts with the
java.net.preferIPv4Stack setting set to true?
               Jack