OK - so option 3. was the correct one - however you also need to download xulrunner (install to usr/lib) from mozilla website and make sure that the option is added at the end of the .ini file.

esbox.ini

-startup
plugins/org.eclipse.equinox.launcher_1.0.101.R34x_v2008112 5.jar
--launcher.library
plugins/org.eclipse.equinox.launcher.gtk.linux.x86_1.0.101 .R34x_v20080805
-vmargs
-Xms40m
-Xmx800m
-XX:MaxPermSize=128m
-Dorg.eclipse.swt.browser.XULRunnerPath=/usr/lib/xulrunner