Use old JavaFX versions in Java 8

I would like to use an old JavaFX version in my web launcher application. It worked fine with Java 7, but now we're having problems with Java 8. Is there a way to disable loading (in JNLP) jfxrt.jar

, which is by default on the classpath in Java 8? As I understand it, I cannot use the bootclasspath parameter java-vm-args

in JNLP to load old JavaFX jars up to standard jfxrt.jar

Java 8. Are there any solutions or workarounds for this problem?

Thanks in advance.