javaws doesn't open Supermicro remote console (IP-KVM)

When trying to open the IP-KVM (remote console) of my Supermicro X9SCM-F mainboard, I get an error:

net.sourceforge.jnlp.LaunchException: Fatal: Initialization Error: Could not initialize application.
 at net.sourceforge.jnlp.Launcher.createApplication(Launcher.java:778)
 at net.sourceforge.jnlp.Launcher.launchApplication(Launcher.java:552)
 at net.sourceforge.jnlp.Launcher$TgThread.run(Launcher.java:889)
Caused by: net.sourceforge.jnlp.LaunchException: Fatal: Application Error: Cannot grant permissions to unsigned jars. Application requested security permissions, but jars are not signed.
 at net.sourceforge.jnlp.runtime.JNLPClassLoader.setSecurity(JNLPClassLoader.java:312)
 at net.sourceforge.jnlp.runtime.JNLPClassLoader.<init>(JNLPClassLoader.java:232)
 at net.sourceforge.jnlp.runtime.JNLPClassLoader.getInstance(JNLPClassLoader.java:357)
 at net.sourceforge.jnlp.runtime.JNLPClassLoader.getInstance(JNLPClassLoader.java:330)
 at net.sourceforge.jnlp.Launcher.createApplication(Launcher.java:770)
 ... 2 more

This is reported against Fedora as well:

https://bugzilla.redhat.com/show_bug.cgi?id=753960

No difference between openjdk-6 and openjdk-7.

I expect this to work on Ubuntu, just like Dell DRAC, HP ILOM, IBM ... remote IPMI/IP KVM.

The JNLP file was downloaded using Chromium, invocation of javaws was from the shell, but that makes no difference.

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: openjdk-7-jdk 7u9-2.3.4-0ubuntu1.12.10.1
ProcVersionSignature: Ubuntu 3.5.0-23.35-generic 3.5.7.2
Uname: Linux 3.5.0-23-generic x86_64
ApportVersion: 2.6.1-0ubuntu10
Architecture: amd64
Date: Thu Jan 31 22:39:05 2013
InstallationDate: Installed on 2012-11-17 (75 days ago)
InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121017.5)
MarkForUpload: True
SourcePackage: openjdk-7
UpgradeStatus: No upgrade log present (probably fresh install)